The Experts below are selected from a list of 9450 Experts worldwide ranked by ideXlab platform
Ami Aronheim - One of the best experts on this subject based on the ideXlab platform.
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WDR62 mediates TNFα-dependent JNK activation via TRAF2-MLK3 axis.
Molecular biology of the cell, 2018Co-Authors: Elad Prinz, Sharon Aviram, Ami AronheimAbstract:The mitogen-activated protein kinases (MAPKs) regulate a variety of cellular processes. The three main MAPK cascades are the extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinase (JNK), and p38 kinases. A typical MAPK cascade is composed of MAP3K-MAP2K-MAPK kinases that are held by scaffold proteins. Scaffolds function to assemble the protein tier and contribute to the specificity and efficacy of signal transmission. WD repeat domain 62 (WDR62) is a JNK scaffold protein, interacting with JNK, MKK7, and several MAP3Ks. The loss of WDR62 in human leads to microcephaly and pachygyria. Yet the role of WDR62 in cellular function is not fully studied. We used the CRISPR/Cas9 and short hairpin RNA approaches to establish a human breast cancer cell line MDA-MB-231 with WDR62 loss of function and studied the consequence to JNK signaling. In growing cells, WDR62 is responsible for the basal expression of c-Jun. In stressed cells, WDR62 specifically mediates TNFα-dependent JNK activation through the association with both the adaptor protein, TNF receptor-associated factor 2 (TRAF2), and the MAP3K protein, mixed lineage kinase 3. TNFα-dependent JNK activation is mediated by WDR62 in HCT116 and HeLa cell lines as well. MDA-MB-231 WDR62-knockout cells display increased resistance to TNFα-induced cell death. Collectively, WDR62 coordinates the TNFα receptor signaling pathway to JNK activation through association with multiple kinases and the adaptor protein TRAF2.
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The association of the JNK scaffold protein, WDR62, with the mixed lineage kinase 3, MLK3
MAP Kinase, 2015Co-Authors: Miriam Hadad, Alan J Whitmarsh, Sharon Aviram, Ilona Darlyuk-saadon, Ksenya Cohen-katsenelson, Ami AronheimAbstract:Mitogen-activated protein kinases (MAPKs) form a kinase tier module in which MAPK, MAP2K and MAP3K are held by scaffold proteins. The scaffold proteins serve as a protein platform for selective and spatial kinase activation. The precise mechanism by which the scaffold proteins function has not yet been fully explained. WD40-repeat protein 62, WDR62 is a novel scaffold protein of the c-Jun N-terminal kinase (JNK) pathway. WDR62 is a 1523 a.a. long protein with no significant sequence homology to a known gene. Previously WDR62 was shown to associate with JNK and MKK4/7 in a modular fashion. Here, we show that WDR62 is able to associate with multiple members of the MAP3K of the mixed lineage kinase family and we map WDR62-MLK3 interacting domains. We identify two separable interacting domains within WDR62 and MLK3 proteins that can cross associate. MLK3 association with WDR62 is independent of JNK and MKK4/7 domains and activities. CDC42 activation disrupts WDR62-MLK3 association independent of MLK3 kinase activity.
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Identification and Analysis of a Novel Dimerization Domain Shared by Various Members of c-Jun N-terminal Kinase (JNK) Scaffold Proteins
The Journal of biological chemistry, 2013Co-Authors: Ksenya Cohen-katsenelson, Ilona Darlyuk-saadon, Tanya Wasserman, Alona Rabner, Fabian Glaser, Ami AronheimAbstract:Mitogen-activated protein kinases (MAPKs) form a kinase tier module in which MAPK, MAP2K, and MAP3K are held by scaffold proteins. The scaffold proteins serve as a protein platform for selective and spatial kinase activation. The precise mechanism by which the scaffold proteins function has not yet been fully explained. WDR62 is a novel scaffold protein of the c-Jun N-terminal kinase (JNK) pathway. Recessive mutations within WDR62 result in severe cerebral cortical malformations. One of the WDR62 mutant proteins found in a patient with microcephaly encodes a C-terminal truncated protein that fails to associate efficiently with JNK and MKK7β1. The present article shows that the WDR62 C-terminal region harbors a novel dimerization domain composed of a putative loop-helix domain that is necessary and sufficient for WDR62 dimerization and is critical for its scaffolding function. The loop-helix domain is highly conserved between orthologues and is also shared by the JNK scaffold protein, JNKBP1/MAPKBP1. Based on the high sequence conservation of the loop-helix domain, our article shows that MAPKBP1 homodimerizes and heterodimerizes with WDR62. Endogenous WDR62 and MAPKBP1 co-localize to stress granules following arsenite treatment, but not during mitosis. This study proposes another layer of complexity, in which coordinated activation of signaling pathways is mediated by the association between the different JNK scaffold proteins depending on their biological function.
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Docking interactions of the JNK scaffold protein WDR62.
The Biochemical journal, 2011Co-Authors: Ksenya Cohen-katsenelson, Alan J Whitmarsh, Tanya Wasserman, Samer Khateb, Ami AronheimAbstract:JNK (c-Jun N-terminal kinase) is part of a MAPK (mitogen-activated protein kinase) signalling cascade. Scaffold proteins simultaneously associate with various components of the MAPK signalling pathway and play a crucial role in signal transmission and MAPK regulation. WDR62 (WD repeat domain 62) is a JNK scaffold protein. Recessive mutations within WDR62 result in severe cerebral cortical malformation. In the present study we demonstrate the association of WDR62 with endogenous and overexpressed proteins of both JNK2 and the JNK2-activating kinase MKK7 (MAPK kinase 7). Association of WDR62 with JNK2 and MKK7 occurs via direct protein-protein interactions. We mapped the docking domain of WDR62 responsible for the association with JNK. WDR62 interacts with all JNK isoforms through a D domain motif located at the C-terminus. A WDR62 mutant lacking the putative JNK-binding domain fails to activate and recruit JNK to cellular granules. Furthermore, a synthetic peptide composed of the WDR62 docking domain inhibits JNK2 activity in vitro. WDR62 association with JNK2 requires both the JNK CD and ED domains, and the binding requisite is distinct from that of the previously described JNK2 association with JIP1 (JNK-interacting protein 1). Next, we characterized the association between WDR62 and MKK7. WDR62 associates directly with the MKK7β1 isoform independently of JNK binding, but fails to interact with MKK7α1. Furthermore, MKK7β1 recruits a protein phosphatase that dephosphorylates WDR62. Interestingly, a premature termination mutation in WDR62 that results in severe brain developmental defects does not abrogate WDR62 association with either JNK or MKK7. Therefore such mutations represent a loss of WDR62 function independent of JNK signalling.
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A Novel c-Jun N-terminal Kinase (JNK)-binding Protein WDR62 Is Recruited to Stress Granules and Mediates a Nonclassical JNK Activation
Molecular biology of the cell, 2009Co-Authors: Tanya Wasserman, Ksenya Cohen Katsenelson, Sharon Daniliuc, Tal Hasin, Mordechay Choder, Ami AronheimAbstract:The c-Jun N-terminal kinase (JNK) is part of a mitogen-activated protein kinase (MAPK) signaling cascade. Scaffold proteins simultaneously associate with various components of the MAPK signaling pathway and play a role in signal transmission and regulation. Here we describe the identification of a novel scaffold JNK-binding protein, WDR62, with no sequence homology to any of the known scaffold proteins. WDR62 is a ubiquitously expressed heat-sensitive 175-kDa protein that specifically associates with JNK but not with ERK and p38. Association between WDR62 and JNKs occurs in the absence and after either transient or persistent stimuli. WDR62 potentiates JNK kinase activity; however it inhibits AP-1 transcription through recruitment of JNK to a nonnuclear compartment. HEK-293T cells transfected with WDR62 display cytoplasmic granular localization. Overexpression of stress granule (SG) resident proteins results in the recruitment of endogenous WDR62 and activated JNK to SG. In addition, cell treatment with arsenite results in recruitment of WDR62 to SG and activated JNK to processing bodies (PB). JNK inhibition results in reduced number and size of SG and reduced size of PB. Collectively, we propose that JNK and WDR62 may regulate the dynamic interplay between polysomes SG and PB, thereby mediating mRNA fate after stress.
Hirofumi Ohashi - One of the best experts on this subject based on the ideXlab platform.
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plk1 mediated phosphorylation of WDR62 mcph2 ensures proper mitotic spindle orientation
Human Molecular Genetics, 2017Co-Authors: Tatsuo Miyamoto, Silvia Natsuko Akutsu, Akihiro Fukumitsu, Hiroyuki Morino, Yoshinori Masatsuna, Kosuke Hosoba, Hideshi Kawakami, Takashi Yamamoto, Kenji Shimizu, Hirofumi OhashiAbstract:Primary microcephaly (MCPH) is an autosomal recessive disorder characterized by congenital reduction of head circumference. Here, we identified compound heterozygous mutations c.731 C > T (p.Ser 244 Leu) and c.2413 G > T (p.Glu 805 X) in the WDR62/MCPH2 gene, which encodes the mitotic centrosomal protein WDR62, in two siblings in a Japanese family with microcephaly using whole-exome sequencing. However, the molecular and cellular pathology of microcephaly caused by WDR62/MCPH2 mutation remains unclear. To clarify the physiological role of WDR62, we used the CRISPR/Cas9 system and single-stranded oligonucleotides as a point-mutation-targeting donor to generate human cell lines with knock-in of WDR62/MCPH2 c.731 C > T (p.Ser 244 Leu) missense mutation. In normal metaphase, the mitotic spindle forms parallel to the substratum to ensure symmetric cell division, while WDR62/MCPH2-mutated cells exhibited a randomized spindle orientation caused by the impaired astral microtubule assembly. It was shown that a mitotic kinase, Polo-like kinase 1 (PLK1), is required for the maintenance of spindle orientation through astral microtubule development. In this study, we demonstrated that WDR62 is a PLK1 substrate that is phosphorylated at Ser 897, and that this phosphorylation at the spindle poles promotes astral microtubule assembly to stabilize spindle orientation. Our findings provide insights into the role of the PLK1-WDR62 pathway in the maintenance of proper spindle orientation.
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PLK1-mediated phosphorylation of WDR62/MCPH2 ensures proper mitotic spindle orientation.
Human molecular genetics, 2017Co-Authors: Tatsuo Miyamoto, Silvia Natsuko Akutsu, Akihiro Fukumitsu, Hiroyuki Morino, Yoshinori Masatsuna, Kosuke Hosoba, Hideshi Kawakami, Takashi Yamamoto, Kenji Shimizu, Hirofumi OhashiAbstract:Primary microcephaly (MCPH) is an autosomal recessive disorder characterized by congenital reduction of head circumference. Here, we identified compound heterozygous mutations c.731 C > T (p.Ser 244 Leu) and c.2413 G > T (p.Glu 805 X) in the WDR62/MCPH2 gene, which encodes the mitotic centrosomal protein WDR62, in two siblings in a Japanese family with microcephaly using whole-exome sequencing. However, the molecular and cellular pathology of microcephaly caused by WDR62/MCPH2 mutation remains unclear. To clarify the physiological role of WDR62, we used the CRISPR/Cas9 system and single-stranded oligonucleotides as a point-mutation-targeting donor to generate human cell lines with knock-in of WDR62/MCPH2 c.731 C > T (p.Ser 244 Leu) missense mutation. In normal metaphase, the mitotic spindle forms parallel to the substratum to ensure symmetric cell division, while WDR62/MCPH2-mutated cells exhibited a randomized spindle orientation caused by the impaired astral microtubule assembly. It was shown that a mitotic kinase, Polo-like kinase 1 (PLK1), is required for the maintenance of spindle orientation through astral microtubule development. In this study, we demonstrated that WDR62 is a PLK1 substrate that is phosphorylated at Ser 897, and that this phosphorylation at the spindle poles promotes astral microtubule assembly to stabilize spindle orientation. Our findings provide insights into the role of the PLK1-WDR62 pathway in the maintenance of proper spindle orientation.
Leonie M. Quinn - One of the best experts on this subject based on the ideXlab platform.
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The Role of WD40-Repeat Protein 62 (MCPH2) in Brain Growth: Diverse Molecular and Cellular Mechanisms Required for Cortical Development
Molecular neurobiology, 2017Co-Authors: Belal Shohayeb, Nicholas R. Lim, Mirella Dottori, Leonie M. QuinnAbstract:Genetic disruptions of spindle/centrosome-associated WD40-repeat protein 62 (WDR62) are causative for autosomal recessive primary microcephaly (MCPH) and a broader range of cortical malformations. Since the identification of WDR62 as encoded by the MCPH2 locus in 2010, recent studies that have deleted/depleted WDR62 in various animal models of cortical development have highlighted conserved functions in brain growth. Here, we provide a timely review of our current understanding of WDR62 contributions in the self-renewal, expansion and fate specification of neural stem and progenitor cells that are critical for neocortical development. Recent studies have revealed multiple functions for WDR62 in the regulation of spindle organization, mitotic progression and the duplication and biased inheritance of centrosomes during asymmetric divisions. We also discuss recently elaborated WDR62 interaction partners that include Aurora and c-Jun N-terminal kinases as part of complex signalling mechanisms that may define its neural functions. These studies provide new insights into the molecular and cellular processes that are required for brain formation and implicated in the genesis of primary microcephaly.
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Glial-Specific Functions of Microcephaly Protein WDR62 and Interaction with the Mitotic Kinase AURKA Are Essential for Drosophila Brain Growth
Stem cell reports, 2017Co-Authors: Nicholas R. Lim, Belal Shohayeb, Olga Zaytseva, Naomi C Mitchell, S. Sean Millard, Leonie M. QuinnAbstract:The second most commonly mutated gene in primary microcephaly (MCPH) patients is wd40-repeat protein 62 (WDR62), but the relative contribution of WDR62 function to the growth of major brain lineages is unknown. Here, we use Drosophila models to dissect lineage-specific WDR62 function(s). Interestingly, although neural stem cell (neuroblast)-specific depletion of WDR62 significantly decreased neuroblast number, brain size was unchanged. In contrast, glial lineage-specific WDR62 depletion significantly decreased brain volume. Moreover, loss of function in glia not only decreased the glial population but also non-autonomously caused neuroblast loss. We further demonstrated that WDR62 controls brain growth through lineage-specific interactions with master mitotic signaling kinase, AURKA. Depletion of AURKA in neuroblasts drives brain overgrowth, which was suppressed by WDR62 co-depletion. In contrast, glial-specific depletion of AURKA significantly decreased brain volume, which was further decreased by WDR62 co-depletion. Thus, dissecting relative contributions of MCPH factors to individual neural lineages will be critical for understanding complex diseases such as microcephaly.
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Aurora A phosphorylation of WD40-repeat protein 62 in mitotic spindle regulation.
Cell cycle (Georgetown Tex.), 2016Co-Authors: Nicholas R. Lim, Marie A Bogoyevitch, Yvonne Y C Yeap, Ching-seng Ang, Nicholas A. Williamson, Leonie M. QuinnAbstract:Mitotic spindle organization is regulated by centrosomal kinases that potentiate recruitment of spindle-associated proteins required for normal mitotic progress including the microcephaly protein WD40-repeat protein 62 (WDR62). WDR62 functions underlie normal brain development as autosomal recessive mutations and WDR62 loss cause microcephaly. Here we investigate the signaling interactions between WDR62 and the mitotic kinase Aurora A (AURKA) that has been recently shown to cooperate to control brain size in mice. The spindle recruitment of WDR62 is closely correlated with increased levels of AURKA following mitotic entry. We showed that depletion of TPX2 attenuated WDR62 localization at spindle poles indicating that TPX2 co-activation of AURKA is required to recruit WDR62 to the spindle. We demonstrated that AURKA activity contributed to the mitotic phosphorylation of WDR62 residues Ser49 and Thr50 and phosphorylation of WDR62 N-terminal residues was required for spindle organization and metaphase chromosome alignment. Our analysis of several MCPH-associated WDR62 mutants (V65M, R438H and V1314RfsX18) that are mislocalized in mitosis revealed that their interactions and phosphorylation by AURKA was substantially reduced consistent with the notion that AURKA is a key determinant of WDR62 spindle recruitment. Thus, our study highlights the role of AURKA signaling in the spatiotemporal control of WDR62 at spindle poles where it maintains spindle organization.
Tanya Wasserman - One of the best experts on this subject based on the ideXlab platform.
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Identification and Analysis of a Novel Dimerization Domain Shared by Various Members of c-Jun N-terminal Kinase (JNK) Scaffold Proteins
The Journal of biological chemistry, 2013Co-Authors: Ksenya Cohen-katsenelson, Ilona Darlyuk-saadon, Tanya Wasserman, Alona Rabner, Fabian Glaser, Ami AronheimAbstract:Mitogen-activated protein kinases (MAPKs) form a kinase tier module in which MAPK, MAP2K, and MAP3K are held by scaffold proteins. The scaffold proteins serve as a protein platform for selective and spatial kinase activation. The precise mechanism by which the scaffold proteins function has not yet been fully explained. WDR62 is a novel scaffold protein of the c-Jun N-terminal kinase (JNK) pathway. Recessive mutations within WDR62 result in severe cerebral cortical malformations. One of the WDR62 mutant proteins found in a patient with microcephaly encodes a C-terminal truncated protein that fails to associate efficiently with JNK and MKK7β1. The present article shows that the WDR62 C-terminal region harbors a novel dimerization domain composed of a putative loop-helix domain that is necessary and sufficient for WDR62 dimerization and is critical for its scaffolding function. The loop-helix domain is highly conserved between orthologues and is also shared by the JNK scaffold protein, JNKBP1/MAPKBP1. Based on the high sequence conservation of the loop-helix domain, our article shows that MAPKBP1 homodimerizes and heterodimerizes with WDR62. Endogenous WDR62 and MAPKBP1 co-localize to stress granules following arsenite treatment, but not during mitosis. This study proposes another layer of complexity, in which coordinated activation of signaling pathways is mediated by the association between the different JNK scaffold proteins depending on their biological function.
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Docking interactions of the JNK scaffold protein WDR62.
The Biochemical journal, 2011Co-Authors: Ksenya Cohen-katsenelson, Alan J Whitmarsh, Tanya Wasserman, Samer Khateb, Ami AronheimAbstract:JNK (c-Jun N-terminal kinase) is part of a MAPK (mitogen-activated protein kinase) signalling cascade. Scaffold proteins simultaneously associate with various components of the MAPK signalling pathway and play a crucial role in signal transmission and MAPK regulation. WDR62 (WD repeat domain 62) is a JNK scaffold protein. Recessive mutations within WDR62 result in severe cerebral cortical malformation. In the present study we demonstrate the association of WDR62 with endogenous and overexpressed proteins of both JNK2 and the JNK2-activating kinase MKK7 (MAPK kinase 7). Association of WDR62 with JNK2 and MKK7 occurs via direct protein-protein interactions. We mapped the docking domain of WDR62 responsible for the association with JNK. WDR62 interacts with all JNK isoforms through a D domain motif located at the C-terminus. A WDR62 mutant lacking the putative JNK-binding domain fails to activate and recruit JNK to cellular granules. Furthermore, a synthetic peptide composed of the WDR62 docking domain inhibits JNK2 activity in vitro. WDR62 association with JNK2 requires both the JNK CD and ED domains, and the binding requisite is distinct from that of the previously described JNK2 association with JIP1 (JNK-interacting protein 1). Next, we characterized the association between WDR62 and MKK7. WDR62 associates directly with the MKK7β1 isoform independently of JNK binding, but fails to interact with MKK7α1. Furthermore, MKK7β1 recruits a protein phosphatase that dephosphorylates WDR62. Interestingly, a premature termination mutation in WDR62 that results in severe brain developmental defects does not abrogate WDR62 association with either JNK or MKK7. Therefore such mutations represent a loss of WDR62 function independent of JNK signalling.
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A Novel c-Jun N-terminal Kinase (JNK)-binding Protein WDR62 Is Recruited to Stress Granules and Mediates a Nonclassical JNK Activation
Molecular biology of the cell, 2009Co-Authors: Tanya Wasserman, Ksenya Cohen Katsenelson, Sharon Daniliuc, Tal Hasin, Mordechay Choder, Ami AronheimAbstract:The c-Jun N-terminal kinase (JNK) is part of a mitogen-activated protein kinase (MAPK) signaling cascade. Scaffold proteins simultaneously associate with various components of the MAPK signaling pathway and play a role in signal transmission and regulation. Here we describe the identification of a novel scaffold JNK-binding protein, WDR62, with no sequence homology to any of the known scaffold proteins. WDR62 is a ubiquitously expressed heat-sensitive 175-kDa protein that specifically associates with JNK but not with ERK and p38. Association between WDR62 and JNKs occurs in the absence and after either transient or persistent stimuli. WDR62 potentiates JNK kinase activity; however it inhibits AP-1 transcription through recruitment of JNK to a nonnuclear compartment. HEK-293T cells transfected with WDR62 display cytoplasmic granular localization. Overexpression of stress granule (SG) resident proteins results in the recruitment of endogenous WDR62 and activated JNK to SG. In addition, cell treatment with arsenite results in recruitment of WDR62 to SG and activated JNK to processing bodies (PB). JNK inhibition results in reduced number and size of SG and reduced size of PB. Collectively, we propose that JNK and WDR62 may regulate the dynamic interplay between polysomes SG and PB, thereby mediating mRNA fate after stress.
Nicholas R. Lim - One of the best experts on this subject based on the ideXlab platform.
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The Role of WD40-Repeat Protein 62 (MCPH2) in Brain Growth: Diverse Molecular and Cellular Mechanisms Required for Cortical Development
Molecular neurobiology, 2017Co-Authors: Belal Shohayeb, Nicholas R. Lim, Mirella Dottori, Leonie M. QuinnAbstract:Genetic disruptions of spindle/centrosome-associated WD40-repeat protein 62 (WDR62) are causative for autosomal recessive primary microcephaly (MCPH) and a broader range of cortical malformations. Since the identification of WDR62 as encoded by the MCPH2 locus in 2010, recent studies that have deleted/depleted WDR62 in various animal models of cortical development have highlighted conserved functions in brain growth. Here, we provide a timely review of our current understanding of WDR62 contributions in the self-renewal, expansion and fate specification of neural stem and progenitor cells that are critical for neocortical development. Recent studies have revealed multiple functions for WDR62 in the regulation of spindle organization, mitotic progression and the duplication and biased inheritance of centrosomes during asymmetric divisions. We also discuss recently elaborated WDR62 interaction partners that include Aurora and c-Jun N-terminal kinases as part of complex signalling mechanisms that may define its neural functions. These studies provide new insights into the molecular and cellular processes that are required for brain formation and implicated in the genesis of primary microcephaly.
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Glial-Specific Functions of Microcephaly Protein WDR62 and Interaction with the Mitotic Kinase AURKA Are Essential for Drosophila Brain Growth
Stem cell reports, 2017Co-Authors: Nicholas R. Lim, Belal Shohayeb, Olga Zaytseva, Naomi C Mitchell, S. Sean Millard, Leonie M. QuinnAbstract:The second most commonly mutated gene in primary microcephaly (MCPH) patients is wd40-repeat protein 62 (WDR62), but the relative contribution of WDR62 function to the growth of major brain lineages is unknown. Here, we use Drosophila models to dissect lineage-specific WDR62 function(s). Interestingly, although neural stem cell (neuroblast)-specific depletion of WDR62 significantly decreased neuroblast number, brain size was unchanged. In contrast, glial lineage-specific WDR62 depletion significantly decreased brain volume. Moreover, loss of function in glia not only decreased the glial population but also non-autonomously caused neuroblast loss. We further demonstrated that WDR62 controls brain growth through lineage-specific interactions with master mitotic signaling kinase, AURKA. Depletion of AURKA in neuroblasts drives brain overgrowth, which was suppressed by WDR62 co-depletion. In contrast, glial-specific depletion of AURKA significantly decreased brain volume, which was further decreased by WDR62 co-depletion. Thus, dissecting relative contributions of MCPH factors to individual neural lineages will be critical for understanding complex diseases such as microcephaly.
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Aurora A phosphorylation of WD40-repeat protein 62 in mitotic spindle regulation.
Cell cycle (Georgetown Tex.), 2016Co-Authors: Nicholas R. Lim, Marie A Bogoyevitch, Yvonne Y C Yeap, Ching-seng Ang, Nicholas A. Williamson, Leonie M. QuinnAbstract:Mitotic spindle organization is regulated by centrosomal kinases that potentiate recruitment of spindle-associated proteins required for normal mitotic progress including the microcephaly protein WD40-repeat protein 62 (WDR62). WDR62 functions underlie normal brain development as autosomal recessive mutations and WDR62 loss cause microcephaly. Here we investigate the signaling interactions between WDR62 and the mitotic kinase Aurora A (AURKA) that has been recently shown to cooperate to control brain size in mice. The spindle recruitment of WDR62 is closely correlated with increased levels of AURKA following mitotic entry. We showed that depletion of TPX2 attenuated WDR62 localization at spindle poles indicating that TPX2 co-activation of AURKA is required to recruit WDR62 to the spindle. We demonstrated that AURKA activity contributed to the mitotic phosphorylation of WDR62 residues Ser49 and Thr50 and phosphorylation of WDR62 N-terminal residues was required for spindle organization and metaphase chromosome alignment. Our analysis of several MCPH-associated WDR62 mutants (V65M, R438H and V1314RfsX18) that are mislocalized in mitosis revealed that their interactions and phosphorylation by AURKA was substantially reduced consistent with the notion that AURKA is a key determinant of WDR62 spindle recruitment. Thus, our study highlights the role of AURKA signaling in the spatiotemporal control of WDR62 at spindle poles where it maintains spindle organization.
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Opposing roles for JNK and Aurora A in regulating the association of WDR62 with spindle microtubules.
Journal of cell science, 2015Co-Authors: Nicholas R. Lim, Yvonne Y C Yeap, Yan Y Yip, Teresa T Zhao, Shu C Wong, Ching-seng Ang, Nicholas A. Williamson, Marie A BogoyevitchAbstract:WD40-repeat protein 62 (WDR62) is a spindle pole protein required for normal cell division and neuroprogenitor differentiation during brain development. Microcephaly-associated mutations in WDR62 lead to mitotic mislocalization, highlighting a crucial requirement for precise WDR62 spatiotemporal distribution, although the regulatory mechanisms are unknown. Here, we demonstrate that the WD40-repeat region of WDR62 is required for microtubule association, whereas the disordered C-terminal region regulates cell-cycle-dependent compartmentalization. In agreement with a functional requirement for the WDR62–JNK1 complex during neurogenesis, WDR62 specifically recruits JNK1 (also known as MAPK8), but not JNK2 (also known as MAPK9), to the spindle pole. However, JNK-mediated phosphorylation of WDR62 T1053 negatively regulated microtubule association, and loss of JNK signaling resulted in constitutive WDR62 localization to microtubules irrespective of cell cycle stage. In contrast, we identified that Aurora A kinase (AURKA) and WDR62 were in complex and that AURKA-mediated phosphorylation was required for the spindle localization of WDR62 during mitosis. Our studies highlight complex regulation of WDR62 localization, with opposing roles for JNK and AURKA in determining its spindle association.
