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Andrea Morrione - One of the best experts on this subject based on the ideXlab platform.
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GRB10 nedd4 mediated multiubiquitination of the insulin like growth factor receptor regulates receptor internalization
Journal of Cellular Physiology, 2008Co-Authors: Giada Monami, Velia Emiliozzi, Andrea MorrioneAbstract:The adaptor protein GRB10 is an interacting partner of the IGF-I receptor (IGF-IR) and the insulin receptor (IR). Previous work from our laboratory has established the role of GRB10 as a negative regulator of IGF-IR-dependent cell proliferation. We have shown that GRB10 binds the E3 ubiquitin ligase Nedd4 and promotes IGF-I-stimulated ubiquitination, internalization, and degradation of the IGF-IR, thereby giving rise to long-term attenuation of signaling. Recent biochemical evidence suggests that tyrosine-kinase receptors (RTK) may not be polyubiquitinated but monoubiquitinated at multiple sites (multiubiquitinated). However, the type of ubiquitination of the IGF-IR is still not defined. Here we show that the GRB10/Nedd4 complex upon ligand stimulation mediates multiubiquitination of the IGF-IR, which is required for receptor internalization. Moreover, Nedd4 by promoting IGF-IR ubiquitination and internalization contributes with GRB10 to negatively regulate IGF-IR-dependent cell proliferation. We also demonstrate that the IGF-IR is internalized through clathrin-dependent and-independent pathways. GRB10 and Nedd4 remain associated with the IGF-IR in early endosomes and caveosomes, where they may participate in sorting internalized receptors. GRB10 and Nedd4, unlike the IGF-IR, which is targeted for lysosomal degradation are not degraded and likely directed into recycling endosomes. These results indicate that GRB10 and Nedd4 play a critical role in mediating IGF-IR down-regulation by promoting ligand-dependent multiubiquitination of the IGF-IR, which is required for receptor internalization and regulates mitogenesis.
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GRB10/Nedd4-mediated multiubiquitination of the insulin-like growth factor receptor regulates receptor internalization
Journal of cellular physiology, 2008Co-Authors: Giada Monami, Velia Emiliozzi, Andrea MorrioneAbstract:The adaptor protein GRB10 is an interacting partner of the IGF-I receptor (IGF-IR) and the insulin receptor (IR). Previous work from our laboratory has established the role of GRB10 as a negative regulator of IGF-IR-dependent cell proliferation. We have shown that GRB10 binds the E3 ubiquitin ligase Nedd4 and promotes IGF-I-stimulated ubiquitination, internalization, and degradation of the IGF-IR, thereby giving rise to long-term attenuation of signaling. Recent biochemical evidence suggests that tyrosine-kinase receptors (RTK) may not be polyubiquitinated but monoubiquitinated at multiple sites (multiubiquitinated). However, the type of ubiquitination of the IGF-IR is still not defined. Here we show that the GRB10/Nedd4 complex upon ligand stimulation mediates multiubiquitination of the IGF-IR, which is required for receptor internalization. Moreover, Nedd4 by promoting IGF-IR ubiquitination and internalization contributes with GRB10 to negatively regulate IGF-IR-dependent cell proliferation. We also demonstrate that the IGF-IR is internalized through clathrin-dependent and-independent pathways. GRB10 and Nedd4 remain associated with the IGF-IR in early endosomes and caveosomes, where they may participate in sorting internalized receptors. GRB10 and Nedd4, unlike the IGF-IR, which is targeted for lysosomal degradation are not degraded and likely directed into recycling endosomes. These results indicate that GRB10 and Nedd4 play a critical role in mediating IGF-IR down-regulation by promoting ligand-dependent multiubiquitination of the IGF-IR, which is required for receptor internalization and regulates mitogenesis.
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GRB10 adapter protein as regulator of insulin like growth factor receptor signaling
Journal of Cellular Physiology, 2003Co-Authors: Andrea MorrioneAbstract:GRB10 is a member of a superfamily of adapter proteins that includes GRB10, 7, 14, and a protein of Caenorhabditis elegans called Mig10. GRB10 proteins are binding partners for several trans-membrane tyrosine-kinase receptors, including the insulin-like growth factor receptor (IGF-IR) and the insulin receptor (IR). Many recent reports have suggested a very important role of GRB10 in regulating IGF-IR signaling. In this review, we will focus on the role of GRB10 in IGF-I-induced mitogenesis and we will discuss the recent findings that show the involvement of GRB10 in the regulation of ligand-induced ubiquitination, internalization, and stability of the IGF-IR.
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GRB10 adapter protein as regulator of insulin-like growth factor receptor signaling.
Journal of cellular physiology, 2003Co-Authors: Andrea MorrioneAbstract:GRB10 is a member of a superfamily of adapter proteins that includes GRB10, 7, 14, and a protein of Caenorhabditis elegans called Mig10. GRB10 proteins are binding partners for several trans-membrane tyrosine-kinase receptors, including the insulin-like growth factor receptor (IGF-IR) and the insulin receptor (IR). Many recent reports have suggested a very important role of GRB10 in regulating IGF-IR signaling. In this review, we will focus on the role of GRB10 in IGF-I-induced mitogenesis and we will discuss the recent findings that show the involvement of GRB10 in the regulation of ligand-induced ubiquitination, internalization, and stability of the IGF-IR. J. Cell. Physiol. 197: 307–311, 2003© 2003 Wiley-Liss, Inc.
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the GRB10 nedd4 complex regulates ligand induced ubiquitination and stability of the insulin like growth factor i receptor
Molecular and Cellular Biology, 2003Co-Authors: Andrea Vecchione, Daniela Rotin, Pauline Henry, Adriano Marchese, Andrea MorrioneAbstract:The adapter protein GRB10 belongs to a superfamily of related proteins, including Grb7, -10, and -14 and Caenorhabditis elegans Mig10. GRB10 is an interacting partner of the insulin-like growth factor I receptor (IGF-IR) and the insulin receptor (IR). Previous work showed an inhibitory effect of mouse GRB10 (mGRB10α) on IGF-I-mediated mitogenesis (A. Morrione et al., J. Biol. Chem. 272:26382-26387, 1997). With mGRB10α as bait in a yeast two-hybrid screen, mouse Nedd4 (mNedd4-1), a ubiquitin protein ligase, was previously isolated as an interacting protein of GRB10 (A. Morrione et al., J. Biol. Chem. 274:24094-24099, 1999). However, GRB10 is not ubiquitinated by Nedd4 in cells. Here we show that in mouse embryo fibroblasts overexpressing GRB10 and the IGF-IR (p6/GRB10), there is a strong ligand-dependent increase in ubiquitination of the IGF-IR compared with that in parental cells (p6). This increased ubiquitination is associated with a shorter half-life and increased internalization of the IGF-IR. The IGF-IR is stabilized following treatment with both MG132 and chloroquine, indicating that both the proteasome and lysosomal pathways mediate degradation of the receptor. Ubiquitination of the IGF-IR likely occurs at the plasma membrane, prior to the formation of endocytic vesicles, as it is insensitive to dansylcadaverine, an inhibitor of early endosome formation in IGF-IR endocytosis. GRB10 coimmunoprecipitates with the IGF-IR and endogenous Nedd4 in p6/GRB10 cells, suggesting the presence of a GRB10/Nedd4/IGF-IR complex. Ubiquitination of the IGF-IR in p6/GRB10 cells is severely impaired by overexpression of a catalytically inactive Nedd4 mutant (Nedd4-CS), which also stabilizes the receptor. Likewise, overexpression of a GRB10 mutant lacking the Src homology 2 (SH2) domain impaired ubiquitination of the IGF-IR in parental p6 and p6/GRB10 cells, indicating that GRB10 binding to Nedd4 is critical for ubiquitination of the receptor. These results suggest a role for the GRB10/Nedd4 complex in regulating ubiquitination and stability of the IGF-IR, and they suggest that GRB10 serves as an adapter to form a bridge between Nedd4 and the IGF-IR. This is the first demonstration of regulation of stability of a tyrosine kinase receptor by the Nedd4 (HECT) family of E3 ligases.
Andrew Ward - One of the best experts on this subject based on the ideXlab platform.
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Mice carrying paternal knockout of imprinted GRB10 do not show compulsive behaviours
2020Co-Authors: Kira D. A. Rienecker, Andrew Ward, Alexander T. Chavasse, Kim Moorwood, Trevor Humby, Anthony Roger IslesAbstract:Mice lacking paternal expression of imprinted GRB10 show a number of social behaviour deficits, including an enhanced allogrooming phenotype. However, this could also index compulsive behaviour, and the increased whisker barbering seen in GRB10+/p mice has been suggested to be indicative of a trichotillomania-type behaviour. Here we test whether compulsive behaviour is a more general phenotype in GRB10+/p mice by examining marble burying at three different adult ages (2, 6 and 10 months). We also examined the mice for potentially confounding anxiety phenotyes using the elevated plus maze (EPM). GRB10+/p mice showed no difference from wild-type littermate controls on any measure in the marble burying test at any age. There was no difference in standard anxiety measures either, although GRB10+/p mice displayed more risk-taking behaviours on the EPM than wild-type mice. These data suggest that GRB10+/p mice are not generally more compulsive, and that the enhanced allogrooming is probably indicative of altered social behaviour. Furthermore, the altered behaviours seen on the EPM adds to other published findings suggesting that GRB10, and imprinted genes more generally, have a role in mediating risk-taking behaviour.
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detailed analysis of paternal knockout GRB10 mice suggests effects on stability of social behavior rather than social dominance
Genes Brain and Behavior, 2020Co-Authors: Kira D. A. Rienecker, Andrew Ward, Alexander T. Chavasse, Kim Moorwood, Anthony Roger IslesAbstract:Imprinted genes are highly expressed in monoaminergic regions of the midbrain and their functions in this area are thought to have an impact on mammalian social behaviors. One such imprinted gene is GRB10, of which the paternal allele is generally recognized as mediating social dominance behavior. However, there has been no detailed study of social dominance in GRB10 +/p mice. Moreover, the original study examined tube‐test behavior in isolated mice 10 months of age. Isolation testing favors more territorial and aggressive behaviors, and does not address social dominance strategies employed in group housing contexts. Furthermore, isolation stress impacts midbrain function and dominance related behavior, often through alterations in monoaminergic signaling. Thus, we undertook a systematic study of GRB10 +/p social rank and dominance behavior within the cage group, using a number of convergent behavioral tests. We examined both male and female mice to account for sex differences and tested cohorts aged 2, 6 and 10 months to examine any developments related to age. We found group‐housed GRB10 +/p mice do not show evidence of enhanced social dominance, but cages containing GRB10 +/p and wild‐type mice lacked the normal correlation between three different measures of social rank. Moreover, a separate study indicated isolation stress induced inconsistent changes in tube test behavior. Taken together, these data suggest future research on GRB10 +/p mice should focus on the stability of social behaviors, rather than dominance per se.
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detailed analysis of paternal knockout GRB10 mice suggests effects on stability of social behavior rather than social dominance
bioRxiv, 2019Co-Authors: Kira D. A. Rienecker, Andrew Ward, Alexander T. Chavasse, Kim Moorwood, Anthony Roger IslesAbstract:Imprinted genes are highly expressed in monoaminergic regions of the midbrain and their functions in this area are thought to have an impact on mammalian social behaviors. One such imprinted gene is GRB10 , of which the paternal allele is currently recognized as mediating social dominance behavior. However, there has been no detailed study of social dominance in GRB10 +/p mice. Moreover, the original study examined tube-test behavior in isolated mice 10 months of age. Isolation testing favors more territorial and aggressive behaviors, and does not address social dominance strategies employed in group housing contexts. Furthermore, isolation stress impacts midbrain function and dominance related behavior, often through alterations in monoaminergic signaling. Thus, we undertook a systematic study of GRB10 +/p social rank and dominance behavior within the cage group, using a number of convergent behavioral tests. We examined both male and female mice to account for sex differences, and tested cohorts aged 2, 6, and 10 months to examine any developments related to age. We found group-housed GRB10 +/p mice do not show evidence of enhanced social dominance, but cages containing GRB10 +/p and wildtype mice lacked the normal correlation between three different measures of social rank. Moreover, a separate study indicated isolation stress induced inconsistent changes in tube test behavior. Taken together, these data suggest future research on GRB10 +/p mice should focus on the stability of social behaviors, rather than dominance per se .
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detailed analysis of paternal knockout GRB10 mice suggests effects on social stability rather than social dominance
bioRxiv, 2018Co-Authors: Kira D. A. Rienecker, Andrew Ward, Alexander T. Chavasse, Kim Moorwood, Anthony Roger IslesAbstract:Imprinted genes are highly expressed in monoaminergic regions of the midbrain and their functions in this area are thought to have an impact on mammalian social behaviors. One such imprinted gene is GRB10, of which the paternal allele is currently recognized as mediating social dominance behavior. However, there has been no detailed study of social dominance in GRB10+/p mice. Moreover, the original study examined tube-test behavior in isolated mice 10 months of age. Isolation testing favors more territorial and aggressive behaviors, and does not address social dominance strategies employed in group housing contexts. Furthermore, isolation stress impacts midbrain function and dominance related behavior, often through alterations in monoaminergic signaling. Thus, we undertook a systematic study of GRB10+/p social rank and dominance behavior within the cage group, using a number of convergent behavioral tests. We examined both male and female mice to account for sex differences, and tested cohorts aged 2, 6, and 10 months to examine any developments related to age. We found group-housed GRB10+/p mice do not show evidence of enhanced social dominance, but cages containing GRB10+/p and wildtype mice lacked the normal correlation between three different measures of social rank. Moreover, a separate study indicated isolation stress induced inconsistent changes in tube test behavior. Taken together, these data suggest future research on GRB10+/p mice should focus on social stability, rather than dominance per se.
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Maternally-inherited GRB10 reduces placental size and efficiency
Developmental biology, 2009Co-Authors: Marika Charalambous, Florentia M Smith, Michael Cowley, Fleur Geoghegan, Elizabeth J. Radford, Benjamin P. Marlow, Christopher F. Graham, Laurence D. Hurst, Andrew WardAbstract:The control of foetal growth is poorly understood and yet it is critically important that at birth the body has attained appropriate size and proportions. Growth and survival of the mammalian foetus is dependent upon a functional placenta throughout most of gestation. A few genes are known that influence both foetal and placental growth and might therefore coordinate growth of the conceptus, including the imprinted Igf2 and GRB10 genes. GRB10 encodes a signalling adapter protein, is expressed predominantly from the maternally-inherited allele and acts to restrict foetal and placental growth. Here, we show that following disruption of the maternal allele in mice, the labyrinthine volume was increased in a manner consistent with a cell-autonomous function of GRB10 and the enlarged placenta was more efficient in supporting foetal growth. Thus, GRB10 is the first example of a gene that acts to limit placental size and efficiency. In addition, we found that females inheriting a mutant GRB10 allele from their mother had larger litters and smaller offspring than those inheriting a mutant allele from their father. This grandparental effect suggests GRB10 can influence reproductive strategy through the allocation of maternal resources such that offspring number is offset against size.
Anne-françoise Burnol - One of the best experts on this subject based on the ideXlab platform.
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Regulation of insulin and type 1 insulin‐like growth factor signaling and action by the GRB10/14 and SH2B1/B2 adaptor proteins
The FEBS journal, 2013Co-Authors: Bernard Desbuquois, Nadege Carre, Anne-françoise BurnolAbstract:The effects of insulin and type 1 insulin-like growth factor (IGF–1) on metabolism, growth and survival are mediated by their association with specific receptor tyrosine kinases, which results in both receptor and substrate phosphorylation. Phosphotyrosine residues on receptors and substrates provide docking sites for signaling proteins containing SH2 (Src homology 2) domains, including molecular adaptors. This review focuses on the regulation of insulin/IGF–1 signaling and action by two adaptor families with a similar domain organization: the growth factor receptor-bound proteins Grb7/10/14 and the SH2B proteins. Both GRB10/14 and SH2B1/B2 associate with the activation loop of insulin/IGF–1 receptors through their SH2 domains, but association of GRB10/14 also involves their unique BPS domain. Consistent with Grb14 binding as a pseudosubstrate to the kinase active site, insulin/IGF-induced activation of receptors and downstream signaling pathways in cultured cells is inhibited by GRB10/14 adaptors, but is potentiated by SH2B1/B2 adaptors. Accordingly, GRB10 and Grb14 knockout mice show improved insulin/IGF sensitivity in vivo, and, for GRB10, overgrowth and increased skeketal muscle and pancreatic β–cell mass. Conversely, SH2B1-depleted mice display insulin and IGF–1 resistance, with peripheral depletion leading to reduced adiposity and neuronal depletion leading to obesity through associated leptin resistance. GRB10/14 and SH2B1 adaptors also modulate insulin/IGF–1 action by interacting with signaling components downstream of receptors and exert several tissue-specific effects. The identification of GRB10/14 and SH2B1 as physiological regulators of insulin signaling and action, together with observations that variants at their gene loci are associated with obesity and/or insulin resistance, highlight them as potential therapeutic targets for these conditions.
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regulation of insulin and type 1 insulin like growth factor signaling and action by the GRB10 14 and sh2b1 b2 adaptor proteins
FEBS Journal, 2012Co-Authors: Bernard Desbuquois, Nadege Carre, Anne-françoise BurnolAbstract:The effects of insulin and type 1 insulin-like growth factor (IGF–1) on metabolism, growth and survival are mediated by their association with specific receptor tyrosine kinases, which results in both receptor and substrate phosphorylation. Phosphotyrosine residues on receptors and substrates provide docking sites for signaling proteins containing SH2 (Src homology 2) domains, including molecular adaptors. This review focuses on the regulation of insulin/IGF–1 signaling and action by two adaptor families with a similar domain organization: the growth factor receptor-bound proteins Grb7/10/14 and the SH2B proteins. Both GRB10/14 and SH2B1/B2 associate with the activation loop of insulin/IGF–1 receptors through their SH2 domains, but association of GRB10/14 also involves their unique BPS domain. Consistent with Grb14 binding as a pseudosubstrate to the kinase active site, insulin/IGF-induced activation of receptors and downstream signaling pathways in cultured cells is inhibited by GRB10/14 adaptors, but is potentiated by SH2B1/B2 adaptors. Accordingly, GRB10 and Grb14 knockout mice show improved insulin/IGF sensitivity in vivo, and, for GRB10, overgrowth and increased skeketal muscle and pancreatic β–cell mass. Conversely, SH2B1-depleted mice display insulin and IGF–1 resistance, with peripheral depletion leading to reduced adiposity and neuronal depletion leading to obesity through associated leptin resistance. GRB10/14 and SH2B1 adaptors also modulate insulin/IGF–1 action by interacting with signaling components downstream of receptors and exert several tissue-specific effects. The identification of GRB10/14 and SH2B1 as physiological regulators of insulin signaling and action, together with observations that variants at their gene loci are associated with obesity and/or insulin resistance, highlight them as potential therapeutic targets for these conditions.
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Modulation de la sensibilité à l’insuline par les adapteurs moléculaires de la famille de Grb7
Obésité, 2011Co-Authors: Nadege Carre, D. Goenaga, Anne-françoise BurnolAbstract:The Grb7 family of proteins recently emerged as inhibitors of insulin action. The generation of genetic mouse models allowed demonstrating their physiological role in the control of insulin sensitivity and energy metabolism. Their molecular mechanism of action involves a direct inhibition of the insulin receptor catalytic activity and also more distal interferences in insulin signaling pathways that are not yet fully described. The pharmacological inhibition of GRB10/14 action could be a new approach to improve insulin sensitivity and glucose homeostasy.RésuméLes protéines de la famille de Grb7 ( growth factor binding protein 7 ), dont GRB10 et Grb14, sont récemment apparues comme étant des inhibiteurs de l’action de l’insuline. Leur rôle a été démontré à l’aide de modèles génétiques murins. Le mécanisme moléculaire de l’action de ces régulateurs implique à la fois un effet direct sur l’activité catalytique du récepteur de l’insuline et des effets plus en aval dans les voies de signalisation. L’inhibition pharmacologique de l’action de GRB10/14 pourrait être une approche innovante pour améliorer la sensibilité à l’insuline et la régulation de l’homéostasie énergétique.
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Inhibition of FGF receptor signalling in Xenopus oocytes: differential effect of Grb7, GRB10 and Grb14.
FEBS Letters, 2003Co-Authors: Katia Cailliau, Anne-françoise Burnol, Véronique Le Marcis, Véronique Béréziat, Dominique Perdereau, Bertrand Cariou, Jean Pierre Vilain, Edith Browaeys-polyAbstract:The role of Grb7 adapters, Grb7, GRB10, and Grb14, was investigated in Xenopus oocytes expressing fibroblast growth factor receptors (FGFR). FGF-induced maturation of FGFR-expressing oocytes was blocked by previous injection of Grb7 or Grb14, but not GRB10. This effect correlated with Grb7/14 binding to the receptor, and inhibition of the Ras-dependent pathway. Interestingly, the phosphorylated insulin receptor interacting region (PIR) and Src 2 homology domains (SH2) of Grb7 and Grb14 were differently implicated in the inhibition of FGFR signalling. This study provided further evidence for specificity of the biological action of the Grb7 adapters on receptor tyrosine kinase signalling.
Heimo Riedel - One of the best experts on this subject based on the ideXlab platform.
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Mitogenic roles of Gab1 and GRB10 as direct cellular partners in the regulation of MAP kinase signaling.
Journal of cellular biochemistry, 2008Co-Authors: Youping Deng, Manchao Zhang, Heimo RiedelAbstract:Functions of signaling mediators GRB10 or Gab1 have been described in mitogenesis but remained disconnected. Here, we report the peptide hormone-dependent direct association between GRB10 and Gab1 and their functional connection in mitogenic signaling via MAP kinase using cultured fibroblasts as a model. In response to PDGF-, IGF-I, or insulin increased levels of GRB10 potentiated cell proliferation or survival whereas dominant-negative, domain-specific GRB10 peptide mimetics attenuated cell proliferation. This response was sensitive to p44/42 MAPK inhibitor but not to p38 MAPK inhibitor. In response to IGF-I or insulin Raf-1, MEK 1/2, and p44/42 MAPK were regulated by GRB10 but not Ras or p38 MAPK. In response to PDGF MEK 1/2, p44/42 MAPK and p38 MAPK were regulated by GRB10 but not Ras or Raf-1. Peptide hormone-dependent co-immunoprecipitation of GRB10 and Gab1 was demonstrated and specifically blocked by a GRB10 SH2 domain peptide mimetic. This domain was sufficient for direct, peptide hormone-dependent association with Gab1 via the Crk binding region. In response to PDGF, IGF-I, or insulin, in a direct comparison, elevated levels of mouse GRB10 delta, or human GRB10 beta or zeta equally potentiated fibroblast proliferation. Proliferation was severely reduced by Gab1 gene disruption whereas an elevated Gab1 gene dose proportionally stimulated GRB10-potentiated cell proliferation. In conclusion, Gab1 and GRB10 function as direct binding partners in the regulation of the mitogenic MAP kinase signal. In cultured fibroblasts, elevated levels of human GRB10 beta, zeta or mouse GRB10 delta comparably potentiate mitogenesis in response to PDGF, IGF-I, or insulin. J. Cell. Biochem. 105: 1172–1182, 2008. © 2008 Wiley-Liss, Inc.
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GRB10 exceeding the boundaries of a common signaling adapter.
Frontiers in Bioscience, 2004Co-Authors: Heimo RiedelAbstract:Growth factor receptor binding protein 10 (GRB10) has been identified as a cellular partner of a number of receptor tyrosine kinases and other signaling mediators, compatible with multiple roles in mitogenic, metabolic, and embryogenic signaling that are also supported by the tissue distribution of GRB10. In particular, a role has been implicated in the regulation of PI 3-kinase signaling downstream of the insulin receptor. At least seven alternative splice variants have been identified within the GRB10 gene, a proposed candidate for some types of human Silver-Russell syndrome. Located on chromosome 7 (human) or 11 (mouse) the gene is oppositely imprinted in both species. GRB10 isoforms are members of a super family of signaling mediators that includes Grb7, Grb14, and Caenorhabditis elegans MIG-10. All mammalian members of this family share a domain structure which is represented by N-terminal (proline) Pro-rich sequences, a homology domain with MIG-10 (GM) which includes a Ras-associating (RA)-like domain, a pleckstrin homology region (PH), a C-terminal Src homology 2 (SH2) domain, and a receptor binding domain located between the PH and the SH2 domains termed BPS. Various GRB10 isoforms have been identified as cellular partners of the insulin receptor (IR) and insulin-like growth factor-I (IGF-I) receptor that provide the best-established regulators of GRB10 signaling. A regulatory role of GRB10 has been established in the respective metabolic and mitogenic responses by numerous lines of experimental evidence. However, the specific contribution of GRB10 was found to be highly dependent on the cellular context including the balance of other signaling mediators that define whether increased GRB10 levels will enhance or restrain a given response. This is supported by observations with super family members Grb7 and Grb14 that may engage in competitive and redundant mechanisms when compared to GRB10. GRB10 gene disruption in the mouse results in embryonal and placental overgrowth. The underlying molecular mechanisms and their interpretation remain open until a more comprehensive analysis will be available which includes the contribution of the Grb7 and Grb14 super family members. From a physiologic perspective at the cellular level increased levels of GRB10 have been shown to stimulate insulin metabolic action or mitogenic growth factor responses whereas peptide mimetics representing individual GRB10 domains were found to act oppositely by inhibiting the respective cellular response. In an alternative experimental context increased cellular levels of GRB10 have repeatedly been shown to inhibit cellular responses and signaling mechanisms. This has been most specifically observed at the level of molecular interactions in vitro. How the various observations relate to the physiologic role of cellular GRB10 remains to be established, also in the context of possible cross-talk to Grb14 and Grb7 signaling. Based on its interactions with a number of signaling mediators including protein kinases, adapters, and enzymes such as a ubiquitin ligase, GRB10 may act as a signaling hub to integrate multiple incoming signals and as a molecular scaffold to help assemble signaling complexes. The specific contribution of GRB10 in a signaling complex may depend on the local stochiometric balance of associating mediators, including the ratio of competing signaling proteins. In this context a constant cellular level of GRB10 may enhance or restrain a specific signaling mechanism depending on the local distribution and balance of specific GRB10 signaling partners. This concept is compatible with the diverse experimental observations on GRB10 function and emphasizes the importance of the specific cellular context to define the consequences of local changes in GRB10 distribution. Thus, to think of GRB10 as either a positive or negative signaling mediator will be inadequate in reflecting the complexity that underlies the final output of the GRB10 signal.
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GRB10: more than a simple adaptor protein.
Frontiers in bioscience : a journal and virtual library, 2004Co-Authors: Mei A. Lim, Heimo Riedel, Feng LiuAbstract:GRB10 is a member of a superfamily of adaptor proteins that includes Grb7 and Grb14. This family of proteins shares a common overall structure, including an N-terminal region harboring a conserved proline-rich motif, a central Pleckstrin homology (PH) domain, a C-terminal Src homology 2 (SH2) domain, and a conserved region located between the PH and the SH2 domains (BPS). GRB10 directly interacts with a number of mitogenic receptor tyrosine kinases including the insulin (IR) and insulin-like growth factor-I (IGF-IR) receptor. GRB10 binds to the regulatory kinase loop of the insulin receptor (IR) via its SH2 and BPS domains. In addition to receptor tyrosine kinases, GRB10 has also been found to interact with non-receptor tyrosine kinases such as Tec and Bcr-Abl, and other cellular signaling molecules such as Raf-1 and the mitogen activated protein (MAP) kinase kinase, MEK. Overexpression of GRB10 has been shown to inhibit or stimulate insulin/IGF-I signaling depending on the expression levels of the specific isoforms, specific cell context, and/or physiologic endpoint. Genetic imprinting of GRB10 has been linked to the congenital disease, Silver-Russell syndrome, which is characterized by pre- and post-natal growth deficiency. This data suggests that GRB10 may function during embryogenesis in regulating insulin/IGF-I signaling as these growth factors play important roles during development. A role of GRB10 as a potent growth inhibitor during was implicated when disruption of the mGRB10 gene in mice resulted in overgrowth of mutant embryos and neonates. GRB10 is expressed in the central nervous system of mice and rats, which suggests that this protein may regulate neuronal insulin signaling and energy metabolism, consistent with its reported role in metabolic insulin action in fat and muscle cells. An important area of future investigation will be to elucidate the mechanism underlying GRB10's ability to regulate peptide hormone action including insulin/IGF-I signaling and to study the physiological role of this adaptor protein in cellular and animal models.
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Growth Factor Receptor-binding Protein 10 (GRB10) as a Partner of Phosphatidylinositol 3-Kinase in Metabolic Insulin Action
The Journal of biological chemistry, 2003Co-Authors: Youping Deng, Yong Wang, Sujoy Bhattacharya, O. Rama Swamy, Ruchi Tandon, Robert Janda, Heimo RiedelAbstract:The regulation of the metabolic insulin response by mouse growth factor receptor-binding protein 10 (GRB10) has been addressed in this report. We find mouse GRB10 to be a critical component of the insulin receptor (IR) signaling complex that provides a functional link between IR and p85 phosphatidylinositol (PI) 3-kinase and regulates PI 3-kinase activity. This regulatory mechanism parallels the established link between IR and p85 via insulin receptor substrate (IRS) proteins. A direct association was demonstrated between GRB10 and p85 but was not observed between GRB10 and IRS proteins. In addition, no effect of mouse GRB10 was observed on the association between IRS-1 and p85, on IRS-1-associated PI 3-kinase activity, or on insulin-mediated activation of IR or IRS proteins. A critical role of mouse GRB10 was observed in the regulation of PI 3-kinase activity and the resulting metabolic insulin response. Dominant-negative GRB10 domains, in particular the SH2 domain, eliminated the metabolic response to insulin in differentiated 3T3-L1 adipocytes. This was consistently observed for glycogen synthesis, glucose and amino acid transport, and lipogenesis. In parallel, the same metabolic responses were substantially elevated by increased levels of GRB10. A similar role of GRB10 was confirmed in mouse L6 cells. In addition to the SH2 domain, the Pro-rich amino-terminal region of GRB10 was implicated in the regulation of PI 3-kinase catalytic activity. These regulatory roles of GRB10 were extended to specific insulin mediators downstream of PI 3-kinase including PKB/Akt, glycogen synthase kinase, and glycogen synthase. In contrast, a regulatory role of GRB10 in parallel insulin response pathways including p70 S6 kinase, ubiquitin ligase Cbl, or mitogen-activated protein kinase p38 was not observed. The dissection of the interaction of mouse GRB10 with p85 and the resulting regulation of PI 3-kinase activity should help elucidate the complexity of the IR signaling mechanism.
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GRB10 a positive stimulatory signaling adapter in platelet derived growth factor bb insulin like growth factor i and insulin mediated mitogenesis
Molecular and Cellular Biology, 1999Co-Authors: Jian Wang, Youping Deng, Heping Dai, Nasim Yousaf, Mustapha Moussaif, Amale Boufelliga, Rama O Swamy, Michelle E Leone, Heimo RiedelAbstract:GRB10 has been described as a cellular partner of several receptor tyrosine kinases, including the insulin receptor (IR) and the insulin-like growth factor I (IGF-I) receptor (IGF-IR). Its cellular role is still unclear and a positive as well as an inhibitory role in mitogenesis depending on the cell context has been implicated. We have tested other mitogenic receptor tyrosine kinases as putative GRB10 partners and have identified the activated forms of platelet-derived growth factor (PDGF) receptor β (PDGFRβ), hepatocyte growth factor receptor (Met), and fibroblast growth factor receptor as candidates. We have mapped Y771 as a PDFGRβ site that is involved in the association with GRB10 via its SH2 domain. We have further investigated the putative role of GRB10 in mitogenesis with four independent experimental strategies and found that all consistently suggested a role as a positive, stimulatory signaling adaptor in normal fibroblasts. (i) Complete GRB10 expression from cDNA with an ecdysone-regulated transient expression system stimulated PDGF-BB-, IGF-I, and insulin- but not epidermal growth factor (EGF)-induced DNA synthesis in an ecdysone dose-responsive fashion. (ii) Microinjection of the (dominant-negative) GRB10 SH2 domain interfered with PDGF-BB- and insulin-induced DNA synthesis. (iii) Alternative experiments were based on cell-permeable fusion peptides with the Drosophila antennapedia homeodomain which effectively traverse the plasma membrane of cultured cells. A cell-permeable GRB10 SH2 domain similarly interfered with PDGF-BB-, IGF-I-, and insulin-induced DNA synthesis. In contrast, a cell-permeable GRB10 Pro-rich putative SH3 domain binding region interfered with IGF-I- and insulin- but not with PDGF-BB- or EGF-induced DNA synthesis. (iv) Transient overexpression of complete GRB10 increased whereas cell-permeable GRB10 SH2 domain fusion peptides substantially decreased the cell proliferation rate (as measured by cell numbers) in normal fibroblasts. These experimental strategies independently suggest that GRB10 functions as a positive, stimulatory, mitogenic signaling adapter in PDGF-BB, IGF-I, and insulin action. This function appears to involve the GRB10 SH2 domain, a novel sequence termed BPS, and the Pro-rich putative SH3 domain binding region in IGF-I- and insulin-mediated mitogenesis. In contrast, PDGF-BB-mediated mitogenesis appears to depend on the SH2 but not on the Pro-rich region and may involve other, unidentified GRB10 domains. Distinct protein domains may help to define specific GRB10 functions in different signaling pathways.
Lowenna J Holt - One of the best experts on this subject based on the ideXlab platform.
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Ablation of GRB10 Specifically in Muscle Impacts Muscle Size and Glucose Metabolism in Mice
Endocrinology, 2018Co-Authors: Lowenna J Holt, Amanda E. Brandon, Lewin Small, Eurwin Suryana, Elaine Preston, Donna Wilks, Nancy Mokbel, Chantal A Coles, Jason D. White, Nigel TurnerAbstract:GRB10 is an adaptor-type signaling protein most highly expressed in tissues involved in insulin action and glucose metabolism, such as muscle, pancreas, and adipose. Germline deletion of GRB10 in mice creates a phenotype with larger muscles and improved glucose homeostasis. However, it has not been determined whether GRB10 ablation specifically in muscle is sufficient to induce hypermuscularity or affect whole body glucose metabolism. In this study we generated muscle-specific GRB10-deficient mice (GRB10-mKO) by crossing GRB10flox/flox mice with mice expressing Cre recombinase under control of the human α-skeletal actin promoter. One-year-old GRB10-mKO mice had enlarged muscles, with greater cross-sectional area of fibers compared with wild-type (WT) mice. This degree of hypermuscularity did not affect whole body glucose homeostasis under basal conditions. However, hyperinsulinemic/euglycemic clamp studies revealed that GRB10-mKO mice had greater glucose uptake into muscles compared with WT mice. Insulin signaling was increased at the level of phospho-Akt in muscle of GRB10-mKO mice compared with WT mice, consistent with a role of GRB10 as a modulator of proximal insulin receptor signaling. We conclude that ablation of GRB10 in muscle is sufficient to affect muscle size and metabolism, supporting an important role for this protein in growth and metabolic pathways.
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GRB10 Deletion Enhances Muscle Cell Proliferation, Differentiation and GLUT4 Plasma Membrane Translocation
Journal of cellular physiology, 2014Co-Authors: Nancy Mokbel, Gregory J. Cooney, Roger J. Daly, Lewin Small, Nigel Turner, Nolan J. Hoffman, Christian M. Girgis, Lowenna J HoltAbstract:GRB10 is an intracellular adaptor protein which binds directly to several growth factor receptors, including those for insulin and insulin-like growth factor receptor-1 (IGF-1), and negatively regulates their actions. GRB10-ablated (GRB10-/-) mice exhibit improved whole body glucose homeostasis and an increase in muscle mass associated specifically with an increase in myofiber number. This suggests that GRB10 may act as a negative regulator of myogenesis. In this study, we investigated in vitro, the molecular mechanisms underlying the increase in muscle mass and the improved glucose metabolism. Primary muscle cells isolated from GRB10-/- mice exhibited increased rates of proliferation and differentiation compared to primary cells isolated from wild-type mice. The improved proliferation capacity was associated with an enhanced phosphorylation of Akt and ERK in the basal state and changes in the expression of key cell cycle progression markers involved in regulating transition of cells from the G1 to S phase (e.g., retinoblastoma (Rb) and p21). The absence of GRB10 also promoted a faster transition to a myogenin positive, differentiated state. Glucose uptake was higher in GRB10-/- primary myotubes in the basal state and was associated with enhanced insulin signaling and an increase in GLUT4 translocation to the plasma membrane. These data demonstrate an important role for GRB10 as a link between muscle growth and metabolism with therapeutic implications for diseases, such as muscle wasting and type 2 diabetes. J. Cell. Physiol. 229: 1753–1764, 2014. © 2014 Wiley Periodicals, Inc.
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GRB10 regulates the development of fiber number in skeletal muscle
The FASEB Journal, 2012Co-Authors: Lowenna J Holt, Roger J. Daly, Nancy Mokbel, Nigel Turner, Sophie Trefely, Timo Kanzleiter, Warren Kaplan, Christopher J Ormandy, Gregory J. CooneyAbstract:GRB10 is an intracellular adaptor protein that acts as a negative regulator of insulin and insulin-like growth factor 1 (IGF1) receptors. Since global deletion of GRB10 in mice causes hypermuscularity, we have characterized the skeletal muscle physiology underlying this phenotype. Compared to wild-type (WT) controls, adult mice deficient in GRB10 have elevated body mass and muscle mass throughout adulthood, up to 12 mo of age. The muscle enlargement is not due to increased myofiber size, but rather an increase in myofiber number (142% of WT, P<0.01). There is no change in myofiber type proportions between WT and GRB10-deficient muscles, nor are the metabolic properties of the muscles altered on GRB10 deletion. Notably, the weight and cross-sectional area of hindlimbs from neonatal mice are increased in GRB10-deficient animals (198 and 137% of WT, respectively, both P<0.001). Functional gene signatures for myogenic signaling and proliferation are up-regulated in GRB10-deficient neonatal muscle. Our findings indicate that GRB10 plays a previously unrecognized role in regulating the development of fiber number during murine embryonic growth. In addition, GRB10-ablated muscle from adult mice shows coordinate gene changes that oppose those of muscle wasting pathologies, highlighting GRB10 as a potential therapeutic target for these conditions.
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GRB10 regulates the development of fiber number in skeletal muscle
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2012Co-Authors: Lowenna J Holt, Roger J. Daly, Nancy Mokbel, Nigel Turner, Sophie Trefely, Timo Kanzleiter, Warren Kaplan, Christopher J Ormandy, Gregory J. CooneyAbstract:GRB10 is an intracellular adaptor protein that acts as a negative regulator of insulin and insulin-like growth factor 1 (IGF1) receptors. Since global deletion of GRB10 in mice causes hypermuscularity, we have characterized the skeletal muscle physiology underlying this phenotype. Compared to wild-type (WT) controls, adult mice deficient in GRB10 have elevated body mass and muscle mass throughout adulthood, up to 12 mo of age. The muscle enlargement is not due to increased myofiber size, but rather an increase in myofiber number (142% of WT, P
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Dual Ablation of GRB10 and Grb14 in Mice Reveals Their Combined Role in Regulation of Insulin Signaling and Glucose Homeostasis
Molecular endocrinology (Baltimore Md.), 2009Co-Authors: Lowenna J Holt, Ruth J. Lyons, Ashleigh S Ryan, Susan M. Beale, Andrew Ward, Gregory J. Cooney, Roger J. DalyAbstract:Growth factor receptor bound (Grb)10 and Grb14 are closely related adaptor proteins that bind directly to the insulin receptor (IR) and regulate insulin-induced IR tyrosine phosphorylation and signaling to IRS-1 and Akt. GRB10- and Grb14-deficient mice both exhibit improved whole-body glucose homeostasis as a consequence of enhanced insulin signaling and, in the case of the former, altered body composition. However, the combined physiological role of these adaptors has remained undefined. In this study we utilize compound gene knockout mice to demonstrate that although deficiency in one adaptor can enhance insulin-induced IRS-1 phosphorylation and Akt activation, insulin signaling is not increased further upon dual ablation of GRB10 and Grb14. Context-dependent limiting mechanisms appear to include IR hypophosphorylation and decreased IRS-1 expression. In addition, the compound knockouts exhibit an increase in lean mass comparable to GRB10-deficient mice, indicating that this reflects a regulatory function specific to GRB10. However, despite the absence of additive effects on insulin signaling and body composition, the double-knockout mice are protected from the impaired glucose tolerance that results from high-fat feeding, whereas protection is not observed with animals deficient for individual adaptors. These results indicate that, in addition to their described effects on IRS-1/Akt, GRB10 and Grb14 may regulate whole-body glucose homeostasis by additional mechanisms and highlight these adaptors as potential therapeutic targets for amelioration of the insulin resistance associated with type 2 diabetes.
