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Chang CJ, Chang MY, Lee YC, Chen KY, Hsu TI, Wu YH, Chuang JY, Kao TJ. Nck2 is essential for limb trajectory selection by spinal motor axons. Dev Dyn 2018; 247:1043-1056. [DOI: 10.1002/dvdy.24656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/02/2018] [Accepted: 07/03/2018] [Indexed: 11/08/2022] Open
Affiliation(s)
- Chih-Ju Chang
- Department of Neurosurgery; Cathay General Hospital; Taipei Taiwan
- School of Medicine; Fu Jen Catholic University; New Taipei Taiwan
- Departemnt of Mechanical Engineering; National Central University; Taiwan
| | - Ming-Yuan Chang
- Division of Neurosurgery, Department of Surgery; Min-Sheng General Hospital; Taiwan
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
| | - Yi-Chao Lee
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Kai-Yun Chen
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Tsung-I Hsu
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Yi-Hsin Wu
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Jian-Ying Chuang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
| | - Tzu-Jen Kao
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology; Taipei Medical University; Taipei Taiwan
- Center for Neurotrauma and Neuroregeneration; Taipei Medical University; Taipei Taiwan
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2
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Willoughby LF, Manent J, Allan K, Lee H, Portela M, Wiede F, Warr C, Meng TC, Tiganis T, Richardson HE. Differential regulation of protein tyrosine kinase signalling by Dock and the PTP61F variants. FEBS J 2017; 284:2231-2250. [PMID: 28544778 DOI: 10.1111/febs.14118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 04/12/2017] [Accepted: 05/19/2017] [Indexed: 01/01/2023]
Abstract
Tyrosine phosphorylation-dependent signalling is coordinated by the opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). There is a growing list of adaptor proteins that interact with PTPs and facilitate the dephosphorylation of substrates. The extent to which any given adaptor confers selectivity for any given substrate in vivo remains unclear. Here we have taken advantage of Drosophila melanogaster as a model organism to explore the influence of the SH3/SH2 adaptor protein Dock on the abilities of the membrane (PTP61Fm)- and nuclear (PTP61Fn)-targeted variants of PTP61F (the Drosophila othologue of the mammalian enzymes PTP1B and TCPTP respectively) to repress PTK signalling pathways in vivo. PTP61Fn effectively repressed the eye overgrowth associated with activation of the epidermal growth factor receptor (EGFR), PTK, or the expression of the platelet-derived growth factor/vascular endothelial growth factor receptor (PVR) or insulin receptor (InR) PTKs. PTP61Fn repressed EGFR and PVR-induced mitogen-activated protein kinase signalling and attenuated PVR-induced STAT92E signalling. By contrast, PTP61Fm effectively repressed EGFR- and PVR-, but not InR-induced tissue overgrowth. Importantly, coexpression of Dock with PTP61F allowed for the efficient repression of the InR-induced eye overgrowth, but did not enhance the PTP61Fm-mediated inhibition of EGFR and PVR-induced signalling. Instead, Dock expression increased, and PTP61Fm coexpression further exacerbated the PVR-induced eye overgrowth. These results demonstrate that Dock selectively enhances the PTP61Fm-mediated attenuation of InR signalling and underscores the specificity of PTPs and the importance of adaptor proteins in regulating PTP function in vivo.
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Affiliation(s)
| | - Jan Manent
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Kirsten Allan
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Han Lee
- Institute of Biochemical Sciences, National Taiwan University, and Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Marta Portela
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Florian Wiede
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Coral Warr
- School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Tzu-Ching Meng
- Institute of Biochemical Sciences, National Taiwan University, and Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tony Tiganis
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Helena E Richardson
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.,Peter MacCallum Department of Oncology, University of Melbourne, Victoria, Australia.,Department of Biochemistry & Molecular Biology, University of Melbourne, Victoria, Australia.,Department of Anatomy & Neuroscience, University of Melbourne, Victoria, Australia
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3
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Pérez-Núñez R, Barraza N, Gonzalez-Jamett A, Cárdenas AM, Barnier JV, Caviedes P. Overexpressed Down Syndrome Cell Adhesion Molecule (DSCAM) Deregulates P21-Activated Kinase (PAK) Activity in an In Vitro Neuronal Model of Down Syndrome: Consequences on Cell Process Formation and Extension. Neurotox Res 2016; 30:76-87. [PMID: 26966010 DOI: 10.1007/s12640-016-9613-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/12/2016] [Accepted: 02/26/2016] [Indexed: 10/22/2022]
Abstract
In humans, Down syndrome (DS) is caused by the presence of an extra copy of autosome 21. The most striking finding in DS patients is intellectual disability and the onset of Alzheimer's disease (AD)-like neuropathology in adulthood. Gene overdose is most likely to underlie both developmental impairments, as well as altered neuronal function in DS. Lately, the disruption of cellular signaling and regulatory pathways has been implicated in DS pathophysiology, and many of such pathways may represent common targets for diverse DS-related genes, which could in turn represent attractive therapeutical targets. In this regard, one DS-related gene Down Syndrome Cell Adhesion Molecule (DSCAM), has important functions in neuronal proliferation, maturation, and synaptogenesis. p21-associated kinases (PAKs) appear as a most interesting possibility for study, as DSCAM is known to regulate the PAKs pathway. Hence, in DS, overexpressed DSCAM could deregulate PAKs activity and affect signaling pathways that regulate synaptic plasticity such as dendritic spine dynamics and axon guidance and growth. In the present work, we used an immortalized cell line derived from the cerebral cortex of an animal model of DS such as the trisomy 16 (Ts16) fetal mouse (named CTb), and a similar cell line established from a normal littermate (named CNh), to study the effect of DSCAM in the PAKs pathway. The present study shows that DSCAM is overexpressed in CTb cells by approximately twofold, compared to CNh cells. Congruently, PAK1, as well as its downstream effectors LIMK and cofilin, stay phosphorylated for longer periods after DSCAM activation in the CTb cells, leading to an altered actin dynamics, expressed as an increased basal F/G ratio and reduced neurite growth, in the trisomic condition. The present work presents the correlation between DSCAM gene overexpression and a dysregulation of the PAK pathway, resulting in altered morphological parameters of neuronal plasticity in the trisomic cell line, namely decreased number and length of processes.
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Affiliation(s)
- Ramón Pérez-Núñez
- Program of Molecular & Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile
| | - Natalia Barraza
- Program of Molecular & Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile
| | | | | | - Jean-Vianney Barnier
- Neuroscience Paris-Saclay Institute, UMR 9197, CNRS-Université Paris-Sud, 91400, Orsay Cedex, France
| | - Pablo Caviedes
- Program of Molecular & Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile.
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4
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Borinskaya S, Velle KB, Campellone KG, Talman A, Alvarez D, Agaisse H, Wu YI, Loew LM, Mayer BJ. Integration of linear and dendritic actin nucleation in Nck-induced actin comets. Mol Biol Cell 2015; 27:247-59. [PMID: 26609071 PMCID: PMC4713129 DOI: 10.1091/mbc.e14-11-1555] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 11/17/2015] [Indexed: 11/22/2022] Open
Abstract
The role of the Nck adaptor protein in balancing linear versus branched actin nucleation in comet tails is evaluated. Nck recruits both linear and branched nucleation-promoting factors, both of which are necessary for the formation of actin comets. The findings highlight a novel role for Nck in pathogen-like actin motility. The Nck adaptor protein recruits cytosolic effectors such as N-WASP that induce localized actin polymerization. Experimental aggregation of Nck SH3 domains at the membrane induces actin comet tails—dynamic, elongated filamentous actin structures similar to those that drive the movement of microbial pathogens such as vaccinia virus. Here we show that experimental manipulation of the balance between unbranched/branched nucleation altered the morphology and dynamics of Nck-induced actin comets. Inhibition of linear, formin-based nucleation with the small-molecule inhibitor SMIFH2 or overexpression of the formin FH1 domain resulted in formation of predominantly circular-shaped actin structures with low mobility (actin blobs). These results indicate that formin-based linear actin polymerization is critical for the formation and maintenance of Nck-dependent actin comet tails. Consistent with this, aggregation of an exclusively branched nucleation-promoting factor (the VCA domain of N-WASP), with density and turnover similar to those of N-WASP in Nck comets, did not reconstitute dynamic, elongated actin comets. Furthermore, enhancement of branched Arp2/3-mediated nucleation by N-WASP overexpression caused loss of the typical actin comet tail shape induced by Nck aggregation. Thus the ratio of linear to dendritic nucleation activity may serve to distinguish the properties of actin structures induced by various viral and bacterial pathogens.
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Affiliation(s)
- Sofya Borinskaya
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT 06030
| | - Katrina B Velle
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Kenneth G Campellone
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Arthur Talman
- Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06519
| | - Diego Alvarez
- Biotechnology Research Institute, University of San Martin, 1650 San Martin, Argentina
| | - Hervé Agaisse
- Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06519
| | - Yi I Wu
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT 06030 Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030
| | - Leslie M Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT 06030
| | - Bruce J Mayer
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT 06030 Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030
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5
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Anjum R, Ayoubian H, Schmitz F. Differential synaptic distribution of the scaffold proteins Cask and Caskin1 in the bovine retina. Mol Cell Neurosci 2014; 62:19-29. [DOI: 10.1016/j.mcn.2014.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/24/2014] [Accepted: 08/10/2014] [Indexed: 11/26/2022] Open
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6
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Zhang G, Chen X, Qiu F, Zhu F, Lei W, Nie J. A novel interaction between the SH2 domain of signaling adaptor protein Nck-1 and the upstream regulator of the Rho family GTPase Rac1 engulfment and cell motility 1 (ELMO1) promotes Rac1 activation and cell motility. J Biol Chem 2014; 289:23112-23122. [PMID: 24928514 DOI: 10.1074/jbc.m114.549550] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nck family proteins function as adaptors to couple tyrosine phosphorylation signals to actin cytoskeleton reorganization. Several lines of evidence indicate that Nck family proteins involve in regulating the activity of Rho family GTPases. In the present study, we characterized a novel interaction between Nck-1 with engulfment and cell motility 1 (ELMO1). GST pull-down and co-immunoprecipitation assay demonstrated that the Nck-1-ELMO1 interaction is mediated by the SH2 domain of Nck-1 and the phosphotyrosine residues at position 18, 216, 395, and 511 of ELMO1. A R308K mutant of Nck-1 (in which the SH2 domain was inactive), or a 4YF mutant of ELMO1 lacking these four phosphotyrosine residues, diminished Nck-1-ELMO1 interaction. Conversely, tyrosine phosphatase inhibitor treatment and overexpression of Src family kinase Hck significantly enhanced Nck-1-ELMO1 interaction. Moreover, wild type Nck-1, but not R308K mutant, significantly augmented the interaction between ELMO1 and constitutively active RhoG (RhoG(V12A)), thus promoted Rac1 activation and cell motility. Taken together, the present study characterized a novel Nck-1-ELMO1 interaction and defined a new role for Nck-1 in regulating Rac1 activity.
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Affiliation(s)
- Guo Zhang
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China and
| | - Xia Chen
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China and
| | - Fanghua Qiu
- Department of Clinical Laboratory, Guangzhou Hospital of Traditional Chinese Medicine, Guangzhou 510515, China
| | - Fengxin Zhu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China and
| | - Wenjing Lei
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China and
| | - Jing Nie
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China and.
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7
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Ditlev JA, Michalski PJ, Huber G, Rivera GM, Mohler WA, Loew LM, Mayer BJ. Stoichiometry of Nck-dependent actin polymerization in living cells. ACTA ACUST UNITED AC 2012; 197:643-58. [PMID: 22613834 PMCID: PMC3365498 DOI: 10.1083/jcb.201111113] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulation of actin dynamics through the Nck/N-WASp (neural Wiskott-Aldrich syndrome protein)/Arp2/3 pathway is essential for organogenesis, cell invasiveness, and pathogen infection. Although many of the proteins involved in this pathway are known, the detailed mechanism by which it functions remains undetermined. To examine the signaling mechanism, we used a two-pronged strategy involving computational modeling and quantitative experimentation. We developed predictions for Nck-dependent actin polymerization using the Virtual Cell software system. In addition, we used antibody-induced aggregation of membrane-targeted Nck SH3 domains to test these predictions and to determine how the number of molecules in Nck aggregates and the density of aggregates affected localized actin polymerization in living cells. Our results indicate that the density of Nck molecules in aggregates is a critical determinant of actin polymerization. Furthermore, results from both computational simulations and experimentation support a model in which the Nck/N-WASp/Arp2/3 stoichiometry is 4:2:1. These results provide new insight into activities involving localized actin polymerization, including tumor cell invasion, microbial pathogenesis, and T cell activation.
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Affiliation(s)
- Jonathon A Ditlev
- Department of Genetics and Developmental Biology, Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, and Richard D Berlin Center for Cell Analysis & Modeling, University of Connecticut Health Center, Farmington, CT 06030, USA
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8
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Regulation of axonal development by the nuclear protein hindsight (pebbled) in the Drosophila visual system. Dev Biol 2010; 344:911-21. [PMID: 20541542 DOI: 10.1016/j.ydbio.2010.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 05/14/2010] [Accepted: 06/03/2010] [Indexed: 11/24/2022]
Abstract
The molecules and networks involved in the process of acquisition and maintenance of the form of a mature neuron are not completely known. Using a misexpression screen we identified the gene hindsight as a gene involved in the process of acquisition of the neuronal morphogenesis in the Drosophila adult nervous system. hindsight encodes a transcription factor known for its role in early developmental processes such as embryonic germ band retraction and dorsal closure, as well as in the establishment of cell morphology, planar cell polarity, and epithelial integrity during retinal development. We describe here a novel function for HNT by showing that both loss and gain of function of HNT affects the pathfinding of the photoreceptors axons. By manipulating the timing and level of HNT expression, together with the number of cells manipulated we show here that the function of HNT in axonal guidance is independent of the HNT functions previously reported in retinal cells. Based on genetic interaction experiments we show that part of HNT function in axonal development is exerted through the regulation of genes involved in the dynamics of the actin cytoskeleton.
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9
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A reciprocal interdependence between Nck and PI(4,5)P(2) promotes localized N-WASp-mediated actin polymerization in living cells. Mol Cell 2010; 36:525-35. [PMID: 19917259 DOI: 10.1016/j.molcel.2009.10.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 07/29/2009] [Accepted: 10/28/2009] [Indexed: 11/21/2022]
Abstract
Modulation of actin dynamics through the N-WASp/Arp2/3 pathway is important in cell locomotion, membrane trafficking, and pathogen infection. Here, we demonstrate that Nck is essential for actin remodeling stimulated by phosphatidylinositol 4,5 bisphosphate (PI(4,5)P(2)) and, conversely, that PI(4,5)P(2) is necessary for localized actin polymerization induced by Nck in vivo. Nck knockdown or knockout suppressed actin comets induced by phosphatidylinositol 5-kinase (PIP5K), and PIP5K stimulated tyrosine phosphorylation of an Nck SH2 domain binding partner, suggesting that Nck couples phosphotyrosine- and phosphoinositide-dependent signals. We show that PI(4,5)P(2) and PIP5K are both enriched at actin comets induced by Nck aggregates and that formation of actin comets was strongly inhibited by coclustering with an inositol 5-phosphatase domain to decrease local PI(4,5)P(2) levels. The extent of Nck-induced actin polymerization was also modulated by PI(4,5)P(2)-sensitive N-WASp mutants. This study uncovers a strong reciprocal interdependence between Nck and PI(4,5)P(2) in promoting localized N-WASp-mediated actin polymerization in cells.
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Kumar A, Molli PR, Pakala SB, Bui Nguyen TM, Rayala SK, Kumar R. PAK thread from amoeba to mammals. J Cell Biochem 2009; 107:579-85. [PMID: 19350548 DOI: 10.1002/jcb.22159] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The p21-activated kinases (PAKs) are signaling nodes that play a crucial role in cellular processes including cell motility, differentiation, survival, gene transcription, and hormone signaling. PAKs are highly conserved family of serine-threonine kinases that act as effector for small GTPases Rac and Cdc42. Most of our knowledge about PAK functions has been derived from genetic approaches in lower organisms and many of these functions are similar to that seen in mammalian cells. In this review, we have summarized the extensive information generated in lower eukaryotes and very briefly discussed the current status of PAKs in humans.
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Affiliation(s)
- Anupam Kumar
- Department of Biochemistry and Molecular Biology, George Washington University Medical Center, Washington, District of Columbia 20037, USA
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11
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Ruusala A, Pawson T, Heldin CH, Aspenström P. Nck adapters are involved in the formation of dorsal ruffles, cell migration, and Rho signaling downstream of the platelet-derived growth factor beta receptor. J Biol Chem 2008; 283:30034-44. [PMID: 18765673 DOI: 10.1074/jbc.m800913200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The SH3 and SH2 domain-containing adapter proteins Nck1 and Nck2 are known to function downstream of activated tyrosine kinase receptors, such as the platelet-derived growth factor (PDGF) receptors. The SH2 domain of Nck1 binds to phosphorylated tyrosine residue 751 in PDGFbeta receptor and has been suggested to have a role in the PDGF-induced mobilization of the actin filament system. Because Tyr-751 is a site for additional receptor interactors, it has been difficult to discriminate the signaling from Nck from signaling via other molecules. For this reason we have used mouse embryonic fibroblasts derived from mice in which the genes for Nck1 and Nck2 have been inactivated by gene targeting (knock-out (KO) cells). The mutant cells had a reduced ability to form edge ruffles in response to PDGF, and the presence of Nck was obligatory for the formation of dorsal ruffles. In addition, the KO cells had a reduced chemotactic and migratory potential. Importantly, KO cells had reduced cell attachment properties and a reduced ability to form focal adhesions in response to serum stimulation. Moreover, signaling involving the Rho GTPases was defective in KO cells. In summary, our observations suggest that the Nck adapters are needed for signaling to Rho GTPases and actin dynamics downstream of the PDGFbeta receptor.
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Affiliation(s)
- Aino Ruusala
- Ludwig Institute for Cancer Research, Biomedical Center, Uppsala University, SE-751 24 Uppsala, Sweden
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12
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Drosophila fragile X mental retardation protein and metabotropic glutamate receptor A convergently regulate the synaptic ratio of ionotropic glutamate receptor subclasses. J Neurosci 2007; 27:12378-89. [PMID: 17989302 DOI: 10.1523/jneurosci.2970-07.2007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A current hypothesis proposes that fragile X mental retardation protein (FMRP), an RNA-binding translational regulator, acts downstream of glutamatergic transmission, via metabotropic glutamate receptor (mGluR) G(q)-dependent signaling, to modulate protein synthesis critical for trafficking ionotropic glutamate receptors (iGluRs) at synapses. However, direct evidence linking FMRP and mGluR function with iGluR synaptic expression is limited. In this study, we use the Drosophila fragile X model to test this hypothesis at the well characterized glutamatergic neuromuscular junction (NMJ). Two iGluR classes reside at this synapse, each containing common GluRIIC (III), IID and IIE subunits, and variable GluRIIA (A-class) or GluRIIB (B-class) subunits. In Drosophila fragile X mental retardation 1 (dfmr1) null mutants, A-class GluRs accumulate and B-class GluRs are lost, whereas total GluR levels do not change, resulting in a striking change in GluR subclass ratio at individual synapses. The sole Drosophila mGluR, DmGluRA, is also expressed at the NMJ. In dmGluRA null mutants, both iGluR classes increase, resulting in an increase in total synaptic GluR content at individual synapses. Targeted postsynaptic dmGluRA overexpression causes the exact opposite GluR phenotype to the dfmr1 null, confirming postsynaptic GluR subtype-specific regulation. In dfmr1; dmGluRA double null mutants, there is an additive increase in A-class GluRs, and a similar additive impact on B-class GluRs, toward normal levels in the double mutants. These results show that both dFMRP and DmGluRA differentially regulate the abundance of different GluR subclasses in a convergent mechanism within individual postsynaptic domains.
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Rohrbough J, Rushton E, Woodruff E, Fergestad T, Vigneswaran K, Broadie K. Presynaptic establishment of the synaptic cleft extracellular matrix is required for post-synaptic differentiation. Genes Dev 2007; 21:2607-28. [PMID: 17901219 PMCID: PMC2000325 DOI: 10.1101/gad.1574107] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Formation and regulation of excitatory glutamatergic synapses is essential for shaping neural circuits throughout development. In a Drosophila genetic screen for synaptogenesis mutants, we identified mind the gap (mtg), which encodes a secreted, extracellular N-glycosaminoglycan-binding protein. MTG is expressed neuronally and detected in the synaptic cleft, and is required to form the specialized transsynaptic matrix that links the presynaptic active zone with the post-synaptic glutamate receptor (GluR) domain. Null mtg embryonic mutant synapses exhibit greatly reduced GluR function, and a corresponding loss of localized GluR domains. All known post-synaptic signaling/scaffold proteins functioning upstream of GluR localization are also grossly reduced or mislocalized in mtg mutants, including the dPix-dPak-Dock cascade and the Dlg/PSD-95 scaffold. Ubiquitous or neuronally targeted mtg RNA interference (RNAi) similarly reduce post-synaptic assembly, whereas post-synaptically targeted RNAi has no effect, indicating that presynaptic MTG induces and maintains the post-synaptic pathways driving GluR domain formation. These findings suggest that MTG is secreted from the presynaptic terminal to shape the extracellular synaptic cleft domain, and that the cleft domain functions to mediate transsynaptic signals required for post-synaptic development.
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Affiliation(s)
- Jeffrey Rohrbough
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Emma Rushton
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Elvin Woodruff
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Tim Fergestad
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Krishanthan Vigneswaran
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
- Corresponding author.E-MAIL ; FAX (615) 936-0129
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14
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Knox S, Ge H, Dimitroff BD, Ren Y, Howe KA, Arsham AM, Easterday MC, Neufeld TP, O'Connor MB, Selleck SB. Mechanisms of TSC-mediated control of synapse assembly and axon guidance. PLoS One 2007; 2:e375. [PMID: 17440611 PMCID: PMC1847706 DOI: 10.1371/journal.pone.0000375] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 03/19/2007] [Indexed: 01/13/2023] Open
Abstract
Tuberous sclerosis complex is a dominant genetic disorder produced by mutations in either of two tumor suppressor genes, TSC1 and TSC2; it is characterized by hamartomatous tumors, and is associated with severe neurological and behavioral disturbances. Mutations in TSC1 or TSC2 deregulate a conserved growth control pathway that includes Ras homolog enriched in brain (Rheb) and Target of Rapamycin (TOR). To understand the function of this pathway in neural development, we have examined the contributions of multiple components of this pathway in both neuromuscular junction assembly and photoreceptor axon guidance in Drosophila. Expression of Rheb in the motoneuron, but not the muscle of the larval neuromuscular junction produced synaptic overgrowth and enhanced synaptic function, while reductions in Rheb function compromised synapse development. Synapse growth produced by Rheb is insensitive to rapamycin, an inhibitor of Tor complex 1, and requires wishful thinking, a bone morphogenetic protein receptor critical for functional synapse expansion. In the visual system, loss of Tsc1 in the developing retina disrupted axon guidance independently of cellular growth. Inhibiting Tor complex 1 with rapamycin or eliminating the Tor complex 1 effector, S6 kinase (S6k), did not rescue axon guidance abnormalities of Tsc1 mosaics, while reductions in Tor function suppressed those phenotypes. These findings show that Tsc-mediated control of axon guidance and synapse assembly occurs via growth-independent signaling mechanisms, and suggest that Tor complex 2, a regulator of actin organization, is critical in these aspects of neuronal development.
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Affiliation(s)
- Sarah Knox
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Hong Ge
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Brian D. Dimitroff
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Yi Ren
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Katie A. Howe
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Andrew M. Arsham
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Mathew C. Easterday
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Thomas P. Neufeld
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Michael B. O'Connor
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Scott B. Selleck
- The Developmental Biology Center, Department of Pediatrics, The University of Minnesota, Minneapolis, Minnesota, United States of America
- The Developmental Biology Center, Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, Minnesota, United States of America
- * To whom correspondence should be addressed. E-mail:
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15
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Shcherbata HR, Yatsenko AS, Patterson L, Sood VD, Nudel U, Yaffe D, Baker D, Ruohola-Baker H. Dissecting muscle and neuronal disorders in a Drosophila model of muscular dystrophy. EMBO J 2007; 26:481-93. [PMID: 17215867 PMCID: PMC1783456 DOI: 10.1038/sj.emboj.7601503] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 11/22/2006] [Indexed: 11/08/2022] Open
Abstract
Perturbation in the Dystroglycan (Dg)-Dystrophin (Dys) complex results in muscular dystrophies and brain abnormalities in human. Here we report that Drosophila is an excellent genetically tractable model to study muscular dystrophies and neuronal abnormalities caused by defects in this complex. Using a fluorescence polarization assay, we show a high conservation in Dg-Dys interaction between human and Drosophila. Genetic and RNAi-induced perturbations of Dg and Dys in Drosophila cause cell polarity and muscular dystrophy phenotypes: decreased mobility, age-dependent muscle degeneration and defective photoreceptor path-finding. Dg and Dys are required in targeting glial cells and neurons for correct neuronal migration. Importantly, we now report that Dg interacts with insulin receptor and Nck/Dock SH2/SH3-adaptor molecule in photoreceptor path-finding. This is the first demonstration of a genetic interaction between Dg and InR.
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Affiliation(s)
- Halyna R Shcherbata
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Andriy S Yatsenko
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Ivan Franko National University in Lviv, Lviv, Ukraine
| | - Larissa Patterson
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Vanita D Sood
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Uri Nudel
- Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - David Yaffe
- Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - David Baker
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Hannele Ruohola-Baker
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Box 357350, Seattle, WA 98195, USA. Tel.: +1 206 543 1710; Fax: +1 206 685 1792; E-mail:
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16
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Rivera GM, Antoku S, Gelkop S, Shin NY, Hanks SK, Pawson T, Mayer BJ. Requirement of Nck adaptors for actin dynamics and cell migration stimulated by platelet-derived growth factor B. Proc Natl Acad Sci U S A 2006; 103:9536-41. [PMID: 16769879 PMCID: PMC1476694 DOI: 10.1073/pnas.0603786103] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The Nck family of Src homology (SH) 2/SH3 domain adaptors functions to link tyrosine phosphorylation induced by extracellular signals with downstream regulators of actin dynamics. We investigated the role of mammalian Nck adaptors in signaling from the activated platelet-derived growth factor (PDGF) receptor (PDGFbetaR) to the actin cytoskeleton. We report here that Nck adaptors are required for cytoskeletal reorganization and chemotaxis stimulated by PDGF-B. Analysis of tyrosine-phosphorylated proteins demonstrated that Crk-associated substrate (p130(Cas)), not the activated PDGFbetaR itself, is the major Nck SH2 domain-binding protein in PDGF-B-stimulated cells. Both Nck- and p130(Cas)-deficient cells fail to display cytoskeletal rearrangements, including the formation of membrane ruffles and the disassembly of actin bundles, typically shown by their WT counterparts in response to PDGF-B. Furthermore, Nck and p130(Cas) colocalize in phosphotyrosine-enriched membrane ruffles induced by PDGF-B in NIH 3T3 cells. These results suggest that Nck adaptors play an essential role in linking the activated PDGFbetaR with actin dynamics through a pathway that involves p130(Cas).
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Affiliation(s)
- G. M. Rivera
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
| | - S. Antoku
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
| | - S. Gelkop
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5; and
| | - N. Y. Shin
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - S. K. Hanks
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - T. Pawson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5; and
- To whom correspondence may be addressed. E-mail:
or
| | - B. J. Mayer
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
- To whom correspondence may be addressed. E-mail:
or
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