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Thomas O. Daniel - One of the best experts on this subject based on the ideXlab platform.
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A mutant Receptor Tyrosine Phosphatase, CD148, causes defects in vascular development.
Molecular and cellular biology, 2003Co-Authors: Takamune Takahashi, Keiko Takahashi, Patricia L. St. John, Paul A. Fleming, Takuya Tomemori, Toshio Watanabe, Dale R. Abrahamson, Christopher J. Drake, Takuji Shirasawa, Thomas O. DanielAbstract:Vascularization defects in genetic recombinant mice have defined critical roles for a number of specific Receptor Tyrosine kinases. Here we evaluated whether an endothelium-expressed Receptor Tyrosine Phosphatase, CD148 (DEP-1/PTPeta), participates in developmental vascularization. A mutant allele, CD148(DeltaCyGFP), was constructed to eliminate CD148 Phosphatase activity by in-frame replacement of cytoplasmic sequences with enhanced green fluorescent protein sequences. Homozygous mutant mice died at midgestation, before embryonic day 11.5 (E11.5), with vascularization failure marked by growth retardation and disorganized vascular structures. Structural abnormalities were observed as early as E8.25 in the yolk sac, prior to the appearance of intraembryonic defects. Homozygous mutant mice displayed enlarged vessels comprised of endothelial cells expressing markers of early differentiation, including VEGFR2 (Flk1), Tal1/SCL, CD31, ephrin-B2, and Tie2, with notable lack of endoglin expression. Increased endothelial cell numbers and mitotic activity indices were demonstrated. At E9.5, homozygous mutant embryos showed homogeneously enlarged primitive vessels defective in vascular remodeling and branching, with impaired pericyte investment adjacent to endothelial structures, in similarity to endoglin-deficient embryos. Developing cardiac tissues showed expanded endocardial projections accompanied by defective endocardial cushion formation. These findings implicate a member of the Receptor Tyrosine Phosphatase family, CD148, in developmental vascular organization and provide evidence that it regulates endothelial proliferation and endothelium-pericyte interactions.
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endothelial localization of Receptor Tyrosine Phosphatase ecrtp dep 1 in developing and mature renal vasculature
Journal of The American Society of Nephrology, 1999Co-Authors: Takamune Takahashi, Keiko Takahashi, Dale R. Abrahamson, Raymond L Mernaugh, Vladimir Drozdoff, Chris Sipe, Harald Schoecklmann, Barry Robert, Thomas O. DanielAbstract:Developmental assembly of the renal microvascula- ture requires spatially and temporally coordinated migration, assembly, differentiation, and maturation of endothelial cells in the context of adjacent epithelial and mesangial cells. In this study, endothelial expression and distribution of the Receptor Tyrosine Phosphatase ECRTP/DEP-1 were evaluated during and after developmental assembly of the renal microvascula- ture. Monoclonal antibodies against ECRTP/DEP-1 ectodo- main epitopes localize its expression to membrane surfaces of endothelial cells in glomerular, peritubular capillary, and arte- rial renal sites of mature human and murine kidney. During kidney development, ECRTP/DEP-1 immunostaining is evi- dent on a subpopulation of metanephric mesenchymal cells and on putative progenitors of glomerular capillary endothelial cells early in their recruitment to developing glomeruli. ECRTP/DEP-1 is prominently displayed on luminal membrane surfaces with punctate accumulations at inter-endothelial con- tacts that overlap with vascular endothelial-cadherin staining. ECRTP/DEP-1 is recruited to inter-endothelial contacts in con- fluent cultured human renal and dermal microvascular endo- thelial cells, yet experimental dissociation of vascular endothe- lial-cadherin from endothelial junctional complexes fails to redistribute ECRTP/DEP-1. These findings indicate that ECRTP/DEP-1 is expressed in anticipation of glomerular cap- illary endothelial recruitment during development, and suggest that ECRTP/DEP-1 ectodomain interacts with endothelial sur- face ligands that are engaged by cell-cell contact.
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Endothelial Localization of Receptor Tyrosine Phosphatase, ECRTP/DEP-1, in Developing and Mature Renal Vasculature
Journal of the American Society of Nephrology : JASN, 1999Co-Authors: Takamune Takahashi, Keiko Takahashi, Dale R. Abrahamson, Raymond L Mernaugh, Vladimir Drozdoff, Chris Sipe, Harald Schoecklmann, Barry Robert, Thomas O. DanielAbstract:Developmental assembly of the renal microvascula- ture requires spatially and temporally coordinated migration, assembly, differentiation, and maturation of endothelial cells in the context of adjacent epithelial and mesangial cells. In this study, endothelial expression and distribution of the Receptor Tyrosine Phosphatase ECRTP/DEP-1 were evaluated during and after developmental assembly of the renal microvascula- ture. Monoclonal antibodies against ECRTP/DEP-1 ectodo- main epitopes localize its expression to membrane surfaces of endothelial cells in glomerular, peritubular capillary, and arte- rial renal sites of mature human and murine kidney. During kidney development, ECRTP/DEP-1 immunostaining is evi- dent on a subpopulation of metanephric mesenchymal cells and on putative progenitors of glomerular capillary endothelial cells early in their recruitment to developing glomeruli. ECRTP/DEP-1 is prominently displayed on luminal membrane surfaces with punctate accumulations at inter-endothelial con- tacts that overlap with vascular endothelial-cadherin staining. ECRTP/DEP-1 is recruited to inter-endothelial contacts in con- fluent cultured human renal and dermal microvascular endo- thelial cells, yet experimental dissociation of vascular endothe- lial-cadherin from endothelial junctional complexes fails to redistribute ECRTP/DEP-1. These findings indicate that ECRTP/DEP-1 is expressed in anticipation of glomerular cap- illary endothelial recruitment during development, and suggest that ECRTP/DEP-1 ectodomain interacts with endothelial sur- face ligands that are engaged by cell-cell contact.
Kai Zinn - One of the best experts on this subject based on the ideXlab platform.
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Interactions between a Receptor Tyrosine Phosphatase and a Cell Surface Ligand Regulate Axon Guidance and Glial-Neuronal Communication
Neuron, 2013Co-Authors: Hyung-kook Peter Lee, Amy Cording, Jost Vielmetter, Kai ZinnAbstract:We developed a screening method for orphan Receptor ligands, in which cell-surface proteins are expressed in Drosophila embryos from GAL4-dependent insertion lines and ligand candidates identified by the presence of ectopic staining with Receptor fusion proteins. Stranded at second (Sas) binds to the Receptor Tyrosine Phosphatase Ptp10D in embryos and in vitro. Sas and Ptp10D can interact in trans when expressed in cultured cells. Interactions between Sas and Ptp10D on longitudinal axons are required to prevent them from abnormally crossing the midline. Sas is expressed on both neurons and glia, whereas Ptp10D is restricted to CNS axons. We conducted epistasis experiments by overexpressing Sas in glia and examining how the resulting phenotypes are changed by removal of Ptp10D from neurons. We find that neuronal Ptp10D restrains signaling by overexpressed glial Sas, which would otherwise produce strong glial and axonal phenotypes.
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The cell surface Receptor Tartan is a potential in vivo substrate for the Receptor Tyrosine Phosphatase Ptp52F.
Molecular and cellular biology, 2009Co-Authors: Lakshmi Bugga, Anuradha Ratnaparkhi, Kai ZinnAbstract:Receptor-linked protein-Tyrosine Phosphatases (RPTPs) are essential regulators of axon guidance and synaptogenesis in Drosophila, but the signaling pathways in which they function are poorly defined. We identified the cell surface Receptor Tartan (Trn) as a candidate substrate for the neuronal RPTP Ptp52F by using a modified two-hybrid screen with a substrate-trapping mutant of Ptp52F as "bait." Trn can bind to the Ptp52F substrate-trapping mutant in transfected Drosophila S2 cells if v-Src kinase, which phosphorylates Trn, is also expressed. Coexpression of wild-type Ptp52F causes dephosphorylation of v-Src-phosphorylated Trn. To examine the specificity of the interaction in vitro, we incubated Ptp52F-glutathione S-transferase (GST) fusion proteins with pervanadate-treated S2 cell lysates. Wild-type Ptp52F dephosphorylated Trn, as well as most other bands in the lysate. GST "pulldown" experiments demonstrated that the Ptp52F substrate-trapping mutant binds exclusively to phospho-Trn. Wild-type Ptp52F pulled down dephosphorylated Trn, suggesting that it forms a stable Ptp52F-Trn complex that persists after substrate dephosphorylation. To evaluate whether Trn and Ptp52F are part of the same pathway in vivo, we examined motor axon guidance in mutant embryos. trn and Ptp52F mutations produce identical phenotypes affecting the SNa motor nerve. The genes also display dosage-dependent interactions, suggesting that Ptp52F regulates Trn signaling in SNa motor neurons.
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Redundancy and compensation in axon guidance: genetic analysis of the Drosophila Ptp10D/Ptp4E Receptor Tyrosine Phosphatase subfamily
Neural Development, 2008Co-Authors: Mili Jeon, Huong Nguyen, Sami Bahri, Kai ZinnAbstract:Background Drosophila has six Receptor protein Tyrosine Phosphatases (RPTPs), five of which are expressed primarily in neurons. Mutations in all five affect axon guidance, either alone or in combination. Highly penetrant central nervous system (CNS) and motor axon guidance alterations are usually observed only when specific combinations of two or more RPTPs are removed. Here, we examine the sixth RPTP, Ptp4E, which is broadly expressed. Results Ptp4E and Ptp10D are closely related type III RPTPs. Non-drosophilid insect species have only one type III RPTP, which is closest to Ptp10D. We found that Ptp4E mutants are viable and fertile. We then examined Ptp4E Ptp10D double mutants. These die before the larval stage, and have a mild CNS phenotype in which the outer longitudinal 1D4 bundle is frayed. Ptp10D Ptp69D double mutants have a strong CNS phenotype in which 1D4 axons abnormally cross the midline and the outer and middle longitudinal bundles are fused to the inner bundle. To examine if Ptp4E also exhibits synthetic phenotypes in combination with Ptp69D , we made Ptp4E Ptp69D double mutants and Ptp4E Ptp10D Ptp69D triple mutants. No phenotype was observed in the double mutant. The triple mutant phenotype differs from the Ptp10D Ptp69D phenotype in two ways. First, the longitudinal tracts appear more normal than in the double mutant; two or three bundles are observed, although they are disorganized and fused. Second, axons labelled by the SemaIIB-τMyc marker often cross in the wrong commissure. We also examined motor axon guidance, and found that no phenotypes are observed in any Ptp4E double mutant combination. However, triple mutants in which Ptp4E Ptp10D was combined with Ptp69D or Ptp52F exhibited stronger phenotypes than the corresponding Ptp10D double mutants. Conclusion Type III RPTPs are required for viability in Drosophila , since Ptp4E Ptp10D double mutants die before the larval stage. Unlike Ptp10D, Ptp4E appears to be a relatively minor player in the control of axon guidance. Strong phenotypes are only observed in triple mutants in which both type III RPTPs are eliminated together with Ptp69D or Ptp52F. Our results allow us to construct a complete genetic interaction matrix for all six of the RPTPs.
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Redundancy and compensation in axon guidance: genetic analysis of the Drosophila Ptp10D/Ptp4E Receptor Tyrosine Phosphatase subfamily
Neural development, 2008Co-Authors: Mili Jeon, Huong Nguyen, Sami M. Bahri, Kai ZinnAbstract:Background Drosophila has six Receptor protein Tyrosine Phosphatases (RPTPs), five of which are expressed primarily in neurons. Mutations in all five affect axon guidance, either alone or in combination. Highly penetrant central nervous system (CNS) and motor axon guidance alterations are usually observed only when specific combinations of two or more RPTPs are removed. Here, we examine the sixth RPTP, Ptp4E, which is broadly expressed.
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The Heparan Sulfate Proteoglycan Syndecan Is an In Vivo Ligand for the Drosophila LAR Receptor Tyrosine Phosphatase
Current biology : CB, 2005Co-Authors: A. Nicole Fox, Kai ZinnAbstract:Background: Receptor Tyrosine Phosphatases (RPTPs) are essential for axon guidance and synaptogenesis in Drosophila. Each guidance decision made by embryonic motor axons during outgrowth to their muscle targets requires a specific subset of the five neural RPTPs. The logic underlying these requirements, however, is still unclear, partially because the ligands recognized by RPTPs at growth cone choice points have not been identified. RPTPs in general are still “orphan Receptors” because, while they have been found to interact in vitro with many different proteins, their in vivo ligands are unknown. Results: Here we use a new type of deficiency screen to identify the transmembrane heparan sulfate proteoglycan Syndecan (Sdc) as a ligand for the neuronal RPTP LAR. LAR interacts with the glycosaminoglycan chains of Syndecan in vitro with nanomolar affinity. Genetic interaction studies using Sdc and Lar LOF mutations demonstrate that Sdc contributes to LAR’s function in motor axon guidance. We also show that overexpression of Sdc on muscles generates the same phenotype as overexpression of LAR in neurons and that genetic removal of LAR suppresses the phenotype produced by ectopic muscle Sdc. Finally, we show that there is at least one additional, nonproteoglycan, ligand for LAR encoded in the genome. Conclusions: Taken together, our results demonstrate that Sdc on muscles can interact with neuronal LAR in vivo and that binding to Sdc increases LAR’s signaling efficacy. Thus, Sdc is a ligand that can act in trans to positively regulate signal transduction through LAR within neuronal growth cones.
Joseph Schlessinger - One of the best experts on this subject based on the ideXlab platform.
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Induction of neurite outgrowth through contactin and Nr-CAM by extracellular regions of glial Receptor Tyrosine Phosphatase beta.
The Journal of cell biology, 1997Co-Authors: Takeshi Sakurai, Moshe Nativ, Elior Peles, Joseph Schlessinger, Marc Lustig, John J. Hemperly, Martin GrumetAbstract:Receptor protein Tyrosine Phosphatase β (RPTPβ) is expressed as soluble and Receptor forms with common extracellular regions consisting of a carbonic anhydrase domain (C), a fibronectin type III repeat (F), and a unique region called S. We showed previously that a recombinant Fc fusion protein with the C domain (βC) binds to contactin and supports neuronal adhesion and neurite growth. As a substrate, βCFS was less effective in supporting cell adhesion, but it was a more effective promoter of neurite outgrowth than βCF. βS had no effect by itself, but it potentiated neurite growth when mixed with βCF. Neurite outgrowth induced by βCFS was inhibited by antibodies against Nr-CAM and contactin, and these cell adhesion molecules formed a complex that bound βCFS. NIH3T3 cells transfected to express βCFS on their surfaces induced neuronal differentiation in culture. These results suggest that binding of glial RPTPβ to the contactin/Nr-CAM complex is important for neurite growth and neuronal differentiation.
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Receptor Tyrosine Phosphatase beta is expressed in the form of proteoglycan and binds to the extracellular matrix protein tenascin.
The Journal of biological chemistry, 1994Co-Authors: Gilad Barnea, Jan Sap, Martin Grumet, Peter Milev, Olli Silvennoinen, Joan B. Levy, Joseph SchlessingerAbstract:The extracellular domain of Receptor type protein Tyrosine Phosphatase beta (RPTP beta) exhibits striking sequence similarity with a soluble, rat brain chondroitin sulfate proteoglycan (3F8 PG). Immunoprecipitation experiments of cells transfected with RPTP beta expression vector and metabolically labeled with [35S]sulfate and [35S]methionine indicate that the transmembrane form of RPTP beta is indeed a chondroitin sulfate proteoglycan. The 3F8 PG is therefore a variant form composed of the entire extracellular domain of RPTP beta probably generated by alternative RNA splicing. Previous immunohistochemical studies indicated that both RPTP beta and the extracellular matrix protein tenascin are localized in similar regions of the central nervous system. We have performed co-aggregation assays with red and green Co-vaspheres coated with tenascin and 3F8 PG, respectively, showing that the extracellular domain of RPTP beta (3F8 PG) binds specifically to tenascin. The interaction between a Receptor Tyrosine Phosphatase and an extracellular matrix protein may have a role in development of the mammalian central nervous system.
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Receptor Tyrosine Phosphatase R-PTP-kappa mediates homophilic binding.
Molecular and cellular biology, 1994Co-Authors: Jan Sap, Ying-ping Jiang, D. Friedlander, Martin Grumet, Joseph SchlessingerAbstract:Receptor Tyrosine Phosphatases (R-PTPases) feature PTPase domains in the context of a Receptor-like transmembrane topology. The R-PTPase R-PTP-kappa displays an extracellular domain composed of fibronectin type III motifs, a single immunoglobulin domain, as well as a recently defined MAM domain (Y.-P. Jiang, H. Wang, P. D'Eustachio, J.M. Musacchio, J. Schlessinger, and J. Sap, Mol. Cell. Biol. 13:2942-2951, 1993). We report here that R-PTP-kappa can mediate homophilic intercellular interaction. Inducible expression of the R-PTP-kappa protein in heterologous cells results in formation of stable cellular aggregates strictly consisting of R-PTP-kappa-expressing cells. Moreover, the purified extracellular domain of R-PTP-kappa functions as a substrate for adhesion by cells expressing R-PTP-kappa and induces aggregation of coated synthetic beads. R-PTP-kappa-mediated intercellular adhesion does not require PTPase activity or posttranslational proteolytic cleavage of the R-PTP-kappa protein and is calcium independent. The results suggest that R-PTPases may provide a link between cell-cell contact and cellular signaling events involving Tyrosine phosphorylation.
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A novel Receptor Tyrosine Phosphatase-sigma that is highly expressed in the nervous system.
The Journal of biological chemistry, 1993Co-Authors: Hai Yan, Olli Silvennoinen, Peter D'eustachio, Albert Grossman, Hong Wang, K. Mossie, Josém. Musacchio, Joseph SchlessingerAbstract:A novel transmembrane Receptor protein Tyrosine Phosphatase-sigma (RPTP-sigma) was cloned from a rat brain stem cDNA library. The extracellular segment of one form of RPTP-sigma contains 824 amino acids and is composed of three immunoglobulin-like and five fibronectin type III (FNIII)-like repeats. The 627-amino acid cytoplasmic region of RPTP-sigma consists of two catalytic domains oriented in tandem. Northern blot analyses indicate that RPTP-sigma is highly expressed in the brain as two major transcripts of 5.7 and 6.9 kilobases (kb). The 5.7-kb transcript is expressed exclusively in the brain while the 6.9-kb species can be detected in the lung and heart, but at significantly lower levels. In situ hybridization studies confirm that RPTP-sigma is localized predominantly in the nervous system and can be detected in the rat as early as embryonic day 12. During embryonic development, RPTP-sigma is expressed extensively in the central and peripheral nervous systems, including the trigeminal and dorsal root ganglia as well as the retina. In adult rat brain, expression is restricted primarily to the olfactory tubercule, cerebellum, and hippocampus. Within the latter structure, RPTP-sigma is present in the pyramidal cell layer and granular layer of the dentate gyrus. Transfection of RPTP-sigma cDNA into human embryonic kidney 293 cells results in the synthesis of a protein with an apparent molecular mass of 200 kDa as detected by immunoprecipitation and immunoblot analyses using polyclonal antibodies against the FNIII-like repeats present in the extracellular domain of RPTP-sigma. The gene for RPTP-sigma has been mapped to distal chromosome 17 in the mouse.
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Ligand-mediated negative regulation of a chimeric transmembrane Receptor Tyrosine Phosphatase
Cell, 1993Co-Authors: Dev M. Desai, Jan Sap, Joseph Schlessinger, Arthur WeissAbstract:CD45, a transmembrane protein Tyrosine Phosphatase (PTPase), is required for TCR signaling. Multiple CD45 isoforms, differing in the extracellular domain, are expressed in a tissue- and activation-specific manner, suggesting an important function for this domain. We report that a chimeric protein in which the extracellular and transmembrane domains of CD45 are replaced with those of the EGF Receptor (EGFR) is able to restore TCR signaling in a CD45-deficient cell. Thus, the cytoplasmic domain of CD45 is necessary and sufficient for TCR signal transduction. Moreover, EGFR ligands functionally inactivate the EGFR-CD45 chimera in a manner that is dependent on dimerization of the chimeric protein. Inactivation of EGFR-CD45 chimera function results in the loss of TCR signaling, indicating that CD45 function is continuously required for TCR-mediated proximal signaling events. These results suggest that ligand-mediated regulation of Receptor-PTPases may have mechanistic similarities with Receptor Tyrosine kinases.
Takamune Takahashi - One of the best experts on this subject based on the ideXlab platform.
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A mutant Receptor Tyrosine Phosphatase, CD148, causes defects in vascular development.
Molecular and cellular biology, 2003Co-Authors: Takamune Takahashi, Keiko Takahashi, Patricia L. St. John, Paul A. Fleming, Takuya Tomemori, Toshio Watanabe, Dale R. Abrahamson, Christopher J. Drake, Takuji Shirasawa, Thomas O. DanielAbstract:Vascularization defects in genetic recombinant mice have defined critical roles for a number of specific Receptor Tyrosine kinases. Here we evaluated whether an endothelium-expressed Receptor Tyrosine Phosphatase, CD148 (DEP-1/PTPeta), participates in developmental vascularization. A mutant allele, CD148(DeltaCyGFP), was constructed to eliminate CD148 Phosphatase activity by in-frame replacement of cytoplasmic sequences with enhanced green fluorescent protein sequences. Homozygous mutant mice died at midgestation, before embryonic day 11.5 (E11.5), with vascularization failure marked by growth retardation and disorganized vascular structures. Structural abnormalities were observed as early as E8.25 in the yolk sac, prior to the appearance of intraembryonic defects. Homozygous mutant mice displayed enlarged vessels comprised of endothelial cells expressing markers of early differentiation, including VEGFR2 (Flk1), Tal1/SCL, CD31, ephrin-B2, and Tie2, with notable lack of endoglin expression. Increased endothelial cell numbers and mitotic activity indices were demonstrated. At E9.5, homozygous mutant embryos showed homogeneously enlarged primitive vessels defective in vascular remodeling and branching, with impaired pericyte investment adjacent to endothelial structures, in similarity to endoglin-deficient embryos. Developing cardiac tissues showed expanded endocardial projections accompanied by defective endocardial cushion formation. These findings implicate a member of the Receptor Tyrosine Phosphatase family, CD148, in developmental vascular organization and provide evidence that it regulates endothelial proliferation and endothelium-pericyte interactions.
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endothelial localization of Receptor Tyrosine Phosphatase ecrtp dep 1 in developing and mature renal vasculature
Journal of The American Society of Nephrology, 1999Co-Authors: Takamune Takahashi, Keiko Takahashi, Dale R. Abrahamson, Raymond L Mernaugh, Vladimir Drozdoff, Chris Sipe, Harald Schoecklmann, Barry Robert, Thomas O. DanielAbstract:Developmental assembly of the renal microvascula- ture requires spatially and temporally coordinated migration, assembly, differentiation, and maturation of endothelial cells in the context of adjacent epithelial and mesangial cells. In this study, endothelial expression and distribution of the Receptor Tyrosine Phosphatase ECRTP/DEP-1 were evaluated during and after developmental assembly of the renal microvascula- ture. Monoclonal antibodies against ECRTP/DEP-1 ectodo- main epitopes localize its expression to membrane surfaces of endothelial cells in glomerular, peritubular capillary, and arte- rial renal sites of mature human and murine kidney. During kidney development, ECRTP/DEP-1 immunostaining is evi- dent on a subpopulation of metanephric mesenchymal cells and on putative progenitors of glomerular capillary endothelial cells early in their recruitment to developing glomeruli. ECRTP/DEP-1 is prominently displayed on luminal membrane surfaces with punctate accumulations at inter-endothelial con- tacts that overlap with vascular endothelial-cadherin staining. ECRTP/DEP-1 is recruited to inter-endothelial contacts in con- fluent cultured human renal and dermal microvascular endo- thelial cells, yet experimental dissociation of vascular endothe- lial-cadherin from endothelial junctional complexes fails to redistribute ECRTP/DEP-1. These findings indicate that ECRTP/DEP-1 is expressed in anticipation of glomerular cap- illary endothelial recruitment during development, and suggest that ECRTP/DEP-1 ectodomain interacts with endothelial sur- face ligands that are engaged by cell-cell contact.
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Endothelial Localization of Receptor Tyrosine Phosphatase, ECRTP/DEP-1, in Developing and Mature Renal Vasculature
Journal of the American Society of Nephrology : JASN, 1999Co-Authors: Takamune Takahashi, Keiko Takahashi, Dale R. Abrahamson, Raymond L Mernaugh, Vladimir Drozdoff, Chris Sipe, Harald Schoecklmann, Barry Robert, Thomas O. DanielAbstract:Developmental assembly of the renal microvascula- ture requires spatially and temporally coordinated migration, assembly, differentiation, and maturation of endothelial cells in the context of adjacent epithelial and mesangial cells. In this study, endothelial expression and distribution of the Receptor Tyrosine Phosphatase ECRTP/DEP-1 were evaluated during and after developmental assembly of the renal microvascula- ture. Monoclonal antibodies against ECRTP/DEP-1 ectodo- main epitopes localize its expression to membrane surfaces of endothelial cells in glomerular, peritubular capillary, and arte- rial renal sites of mature human and murine kidney. During kidney development, ECRTP/DEP-1 immunostaining is evi- dent on a subpopulation of metanephric mesenchymal cells and on putative progenitors of glomerular capillary endothelial cells early in their recruitment to developing glomeruli. ECRTP/DEP-1 is prominently displayed on luminal membrane surfaces with punctate accumulations at inter-endothelial con- tacts that overlap with vascular endothelial-cadherin staining. ECRTP/DEP-1 is recruited to inter-endothelial contacts in con- fluent cultured human renal and dermal microvascular endo- thelial cells, yet experimental dissociation of vascular endothe- lial-cadherin from endothelial junctional complexes fails to redistribute ECRTP/DEP-1. These findings indicate that ECRTP/DEP-1 is expressed in anticipation of glomerular cap- illary endothelial recruitment during development, and suggest that ECRTP/DEP-1 ectodomain interacts with endothelial sur- face ligands that are engaged by cell-cell contact.
Elior Peles - One of the best experts on this subject based on the ideXlab platform.
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Junctional protein MAGI-3 interacts with Receptor Tyrosine Phosphatase beta (RPTP beta) and Tyrosine-phosphorylated proteins.
Journal of cell science, 2003Co-Authors: Konstantin Adamsky, Katya Arnold, Helena Sabanay, Elior PelesAbstract:Receptor protein Tyrosine Phosphatase beta (RPTP beta) mediates cell-cell and cell-matrix interactions. By searching for intracellular proteins that interact with the cytoplasmic region of this Phosphatase using the two-hybrid method, we identified several proteins containing PDZ domains. One of these proteins, MAGI-3, contains a guanylate-kinase-like region, six PDZ and two WW domains. The interaction between RPTP beta and MAGI-3 was confirmed by co-immunoprecipitation and pulldown experiments in transfected cells. Immunofluorescence and immunoelectron microscopy revealed that MAGI-3 is concentrated in specific sites at the plasma membrane and in the nucleus. In epithelial cells, MAGI-3 was localized with ZO-1 and cingulin at tight junctions, whereas in primary cultured astrocytes it was found in E-cadherin-based cell-cell contacts and in focal adhesion sites. Although MAGI-3 itself was not phosphorylated on Tyrosine residues, it became associated with Tyrosine-phosphorylated proteins following a short treatment of the cells with vanadate. In glioblastoma SF763T cells MAGI-3 was associated with a Tyrosine-phosphorylated protein with the apparent molecular weight of 130 kDa, whereas in Caco2 cells it was associated with a 90 kDa protein. Finally, we show that p130 served as a substrate for RPTP beta and that its dephosphorylation required the C-terminal sequence of the Phosphatase, which mediated the interaction with MAGI-3. These findings suggest a possible role for MAGI-3 as a scaffolding molecule that links Receptor Tyrosine Phosphatase with its substrates at the plasma membrane.
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Junctional protein MAGI-3 interacts with Receptor Tyrosine Phosphatase beta (RPTP beta) and Tyrosine-phosphorylated proteins.
Journal of Cell Science, 2003Co-Authors: Konstantin Adamsky, Katya Arnold, Helena Sabanay, Elior PelesAbstract:Receptor protein Tyrosine Phosphatase β (RPTPβ) mediates cell-cell and cell-matrix interactions. By searching for intracellular proteins that interact with the cytoplasmic region of this Phosphatase using the two-hybrid method, we identified several proteins containing PDZ domains. One of these proteins, MAGI-3, contains a guanylate-kinase-like region, six PDZ and two WW domains. The interaction between RPTPβ and MAGI-3 was confirmed by co-immunoprecipitation and pulldown experiments in transfected cells. Immunofluorescence and immunoelectron microscopy revealed that MAGI-3 is concentrated in specific sites at the plasma membrane and in the nucleus. In epithelial cells, MAGI-3 was localized with ZO-1 and cingulin at tight junctions, whereas in primary cultured astrocytes it was found in E-cadherin-based cell-cell contacts and in focal adhesion sites. Although MAGI-3 itself was not phosphorylated on Tyrosine residues, it became associated with Tyrosine-phosphorylated proteins following a short treatment of the cells with vanadate. In glioblastoma SF763T cells MAGI-3 was associated with a Tyrosine-phosphorylated protein with the apparent molecular weight of 130 kDa, whereas in Caco2 cells it was associated with a 90 kDa protein. Finally, we show that p130 served as a substrate for RPTPβ and that its dephosphorylation required the C-terminal sequence of the Phosphatase, which mediated the interaction with MAGI-3. These findings suggest a possible role for MAGI-3 as a scaffolding molecule that links Receptor Tyrosine Phosphatase with its substrates at the plasma membrane.
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Induction of neurite outgrowth through contactin and Nr-CAM by extracellular regions of glial Receptor Tyrosine Phosphatase beta.
The Journal of cell biology, 1997Co-Authors: Takeshi Sakurai, Moshe Nativ, Elior Peles, Joseph Schlessinger, Marc Lustig, John J. Hemperly, Martin GrumetAbstract:Receptor protein Tyrosine Phosphatase β (RPTPβ) is expressed as soluble and Receptor forms with common extracellular regions consisting of a carbonic anhydrase domain (C), a fibronectin type III repeat (F), and a unique region called S. We showed previously that a recombinant Fc fusion protein with the C domain (βC) binds to contactin and supports neuronal adhesion and neurite growth. As a substrate, βCFS was less effective in supporting cell adhesion, but it was a more effective promoter of neurite outgrowth than βCF. βS had no effect by itself, but it potentiated neurite growth when mixed with βCF. Neurite outgrowth induced by βCFS was inhibited by antibodies against Nr-CAM and contactin, and these cell adhesion molecules formed a complex that bound βCFS. NIH3T3 cells transfected to express βCFS on their surfaces induced neuronal differentiation in culture. These results suggest that binding of glial RPTPβ to the contactin/Nr-CAM complex is important for neurite growth and neuronal differentiation.
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the carbonic anhydrase domain of Receptor Tyrosine Phosphatase β is a functional ligand for the axonal cell recognition molecule contactin
Cell, 1995Co-Authors: Elior Peles, Moshe Nativ, Sima Levt, James Schilling, Gilad Barnea, Phillip L Campbell, Douglas O Clary, Takeshi Sakurai, Ricardo Martínez, Gregory D PlowmanAbstract:Abstract Receptor-type protein Tyrosine Phosphatase β (RPTPβ) is expressed in the developing nervous system and contains a carbonic anhydrase (CAH) domain as well as a fibronectin type III repeat in its extracellular domain. Fusion proteins containing these domains were used to search for ligands of RPTPβ. The CAH domain bound specifically to a 140 kDa protein expressed on the surface of neuronal cells. Expression cloning in COS7 cells revealed that this protein is contactin, a GPI membrane-anchored neuronal cell recognition molecule. The CAH domain of RPTPβ induced cell adhesion and neurite growth of primary tectal neurons, and differentiation of neuroblastoma cells. These responses were blocked by antibodies against contactin, demonstrating that contactin is a neuronal Receptor for RPTPβ. These experiments show that an individual domain of RPTPβ acts as a functional ligand for the neuronal Receptor contactin. The interaction between contactin and RPTPβ may generate unidirectional or bidirectional signals during neural development.