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Molecular subversion of Cdc42 signalling in cancer. Biochem Soc Trans 2021; 49:1425-1442. [PMID: 34196668 PMCID: PMC8412110 DOI: 10.1042/bst20200557] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 12/21/2022]
Abstract
Cdc42 is a member of the Rho family of small GTPases and a master regulator of the actin cytoskeleton, controlling cell motility, polarity and cell cycle progression. This small G protein and its regulators have been the subject of many years of fruitful investigation and the advent of functional genomics and proteomics has opened up new avenues of exploration including how it functions at specific locations in the cell. This has coincided with the introduction of new structural techniques with the ability to study small GTPases in the context of the membrane. The role of Cdc42 in cancer is well established but the molecular details of its action are still being uncovered. Here we review alterations found to Cdc42 itself and to key components of the signal transduction pathways it controls in cancer. Given the challenges encountered with targeting small G proteins directly therapeutically, it is arguably the regulators of Cdc42 and the effector signalling pathways downstream of the small G protein which will be the most tractable targets for therapeutic intervention. These will require interrogation in order to fully understand the global signalling contribution of Cdc42, unlock the potential for mapping new signalling axes and ultimately produce inhibitors of Cdc42 driven signalling.
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2
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Tuba Activates Cdc42 during Neuronal Polarization Downstream of the Small GTPase Rab8a. J Neurosci 2021; 41:1636-1649. [PMID: 33478991 DOI: 10.1523/jneurosci.0633-20.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 11/21/2022] Open
Abstract
The acquisition of neuronal polarity is a complex molecular process that depends on changes in cytoskeletal dynamics and directed membrane traffic, regulated by the Rho and Rab families of small GTPases, respectively. However, during axon specification, a molecular link that couples these protein families has yet to be identified. In this paper, we describe a new positive feedback loop between Rab8a and Cdc42, coupled by Tuba, a Cdc42-specific guanine nucleotide-exchange factor (GEF), that ensures a single axon generation in rodent hippocampal neurons from embryos of either sex. Accordingly, Rab8a or Tuba gain-of-function generates neurons with supernumerary axons whereas Rab8a or Tuba loss-of-function abrogated axon specification, phenocopying the well-established effect of Cdc42 on neuronal polarity. Although Rab8 and Tuba do not interact physically, the activity of Rab8 is essential to generate a proximal to distal axonal gradient of Tuba in cultured neurons. Tuba-associated and Rab8a-associated polarity defects are also evidenced in vivo, since dominant negative (DN) Rab8a or Tuba knock-down impairs cortical neuronal migration in mice. Our results suggest that Tuba coordinates directed vesicular traffic and cytoskeleton dynamics during neuronal polarization.SIGNIFICANCE STATEMENT The morphologic, biochemical, and functional differences observed between axon and dendrites, require dramatic structural changes. The extension of an axon that is 1 µm in diameter and grows at rates of up to 500 µm/d, demands the confluence of two cellular processes: directed membrane traffic and fine-tuned cytoskeletal dynamics. In this study, we show that both processes are integrated in a positive feedback loop, mediated by the guanine nucleotide-exchange factor (GEF) Tuba. Tuba connects the activities of the Rab GTPase Rab8a and the Rho GTPase Cdc42, ensuring the generation of a single axon in cultured hippocampal neurons and controlling the migration of cortical neurons in the developing brain. Finally, we provide compelling evidence that Tuba is the GEF that mediates Cdc42 activation during the development of neuronal polarity.
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3
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Cezanne A, Lauer J, Solomatina A, Sbalzarini IF, Zerial M. A non-linear system patterns Rab5 GTPase on the membrane. eLife 2020; 9:e54434. [PMID: 32510320 PMCID: PMC7279886 DOI: 10.7554/elife.54434] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/21/2020] [Indexed: 12/21/2022] Open
Abstract
Proteins can self-organize into spatial patterns via non-linear dynamic interactions on cellular membranes. Modelling and simulations have shown that small GTPases can generate patterns by coupling guanine nucleotide exchange factors (GEF) to effectors, generating a positive feedback of GTPase activation and membrane recruitment. Here, we reconstituted the patterning of the small GTPase Rab5 and its GEF/effector complex Rabex5/Rabaptin5 on supported lipid bilayers. We demonstrate a 'handover' of Rab5 from Rabex5 to Rabaptin5 upon nucleotide exchange. A minimal system consisting of Rab5, RabGDI and a complex of full length Rabex5/Rabaptin5 was necessary to pattern Rab5 into membrane domains. Rab5 patterning required a lipid membrane composition mimicking that of early endosomes, with PI(3)P enhancing membrane recruitment of Rab5 and acyl chain packing being critical for domain formation. The prevalence of GEF/effector coupling in nature suggests a possible universal system for small GTPase patterning involving both protein and lipid interactions.
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Affiliation(s)
- Alice Cezanne
- Max-Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
| | - Janelle Lauer
- Max-Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
| | - Anastasia Solomatina
- Max-Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Chair of Scientific Computing for Systems Biology, Faculty of Computer ScienceDresdenGermany
- MOSAIC Group, Center for Systems Biology DresdenDresdenGermany
| | - Ivo F Sbalzarini
- Max-Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Chair of Scientific Computing for Systems Biology, Faculty of Computer ScienceDresdenGermany
- MOSAIC Group, Center for Systems Biology DresdenDresdenGermany
| | - Marino Zerial
- Max-Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
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Vaidžiulytė K, Coppey M, Schauer K. Intracellular organization in cell polarity - placing organelles into the polarity loop. J Cell Sci 2019; 132:132/24/jcs230995. [PMID: 31836687 DOI: 10.1242/jcs.230995] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Many studies have investigated the processes that support polarity establishment and maintenance in cells. On the one hand, polarity complexes at the cell cortex and their downstream signaling pathways have been assigned as major regulators of polarity. On the other hand, intracellular organelles and their polarized trafficking routes have emerged as important components of polarity. In this Review, we argue that rather than trying to identify the prime 'culprit', now it is time to consider all these players as a collective. We highlight that understanding the intimate coordination between the polarized cell cortex and the intracellular compass that is defined by organelle positioning is essential to capture the concept of polarity. After briefly reviewing how polarity emerges from a dynamic maintenance of cellular asymmetries, we highlight how intracellular organelles and their associated trafficking routes provide diverse feedback for dynamic cell polarity maintenance. We argue that the asymmetric organelle compass is an indispensable element of the polarity network.
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Affiliation(s)
- Kotryna Vaidžiulytė
- Cell Biology and Cancer Unit, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris 75005, France.,Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris 75005, France.,Faculty of Science and Engineering, Sorbonne Université, Paris 75005, France
| | - Mathieu Coppey
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris 75005, France
| | - Kristine Schauer
- Cell Biology and Cancer Unit, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris 75005, France
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5
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Faust JJ, Millis BA, Tyska MJ. Profilin-Mediated Actin Allocation Regulates the Growth of Epithelial Microvilli. Curr Biol 2019; 29:3457-3465.e3. [PMID: 31607529 DOI: 10.1016/j.cub.2019.08.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/17/2019] [Accepted: 08/20/2019] [Indexed: 01/18/2023]
Abstract
Transporting epithelial cells, like those that line the intestinal tract, are specialized for solute processing and uptake. One defining feature is the brush border, an array of microvilli that serves to amplify apical membrane surface area and increase functional capacity. During differentiation, upon exit from stem-cell-containing crypts, enterocytes build thousands of microvilli, each supported by a parallel bundle of actin filaments several microns in length. Given the high concentration of actin residing in mature brush borders, we sought to determine whether enterocytes were resource (i.e., actin monomer) limited in assembling this domain. To examine this possibility, we inhibited Arp2/3, the ubiquitous branched actin nucleator, to increase G-actin availability during brush border assembly. In native intestinal tissues, Arp2/3 inhibition led to increased microvilli length on the surface of crypt, but not villus, enterocytes. In a cell culture model of brush border assembly, Arp2/3 inhibition accelerated the growth and increased the length of microvilli; it also led to a redistribution of F-actin from cortical lateral networks into the brush border. Effects on brush border growth were rescued by treatment with the G-actin sequestering drug, latrunculin A. G-actin binding protein, profilin-1, colocalized in the terminal web with G-actin, and knockdown of this factor compromised brush border growth in a concentration-dependent manner. Finally, the acceleration in brush border assembly induced by Arp2/3 inhibition was abrogated by profilin-1 knockdown. Thus, brush border assembly is limited by G-actin availability, and profilin-1 directs unallocated actin monomers into microvillar core bundles during enterocyte differentiation.
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Affiliation(s)
- James J Faust
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan A Millis
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA; Cell Imaging Shared Resource, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Abstract
Small GTPases are organizers of a plethora of cellular processes. The time and place of their activation are tightly controlled by the localization and activation of their regulators, guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Remarkably, in some systems, the upstream regulators of GTPases are also found downstream of their activity. Resulting feedback loops can generate complex spatiotemporal dynamics of GTPases with important functional consequences. Here we discuss the concept of positive autoregulation of small GTPases by the GEF-effector feedback modules and survey recent developments in this exciting area of cell biology.
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Affiliation(s)
- Andrew B. Goryachev
- Centre for Synthetic and Systems Biology, Institute for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Marcin Leda
- Centre for Synthetic and Systems Biology, Institute for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
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Doi N, Kunimatsu Y, Fujiura K, Togari H, Minagi K, Nakaoji K, Hamada K, Temme A, Tatsuka M. RhoGDIβ affects HeLa cell spindle orientation following UVC irradiation. J Cell Physiol 2019; 234:15134-15146. [PMID: 30652309 DOI: 10.1002/jcp.28154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/02/2019] [Indexed: 01/24/2023]
Abstract
The molecular signals that regulate mitotic spindle orientation to determine the proper division axis play a critical role in the development and maintenance of tissue homeostasis. However, deregulation of signaling events can result in spindle misorientation, which in turn can trigger developmental defects and cancer progression. Little is known about the cellular signaling pathway involved in the misorientation of proliferating cells that evade apoptosis after DNA damage. In this study, we found that perturbations to spindle orientation were induced in ultraviolet C (UVC)-irradiated surviving cells. N-terminal truncated Rho GDP-dissociation inhibitor β (RhoGDIβ), which is produced by UVC irradiation, distorted the spindle orientation of HeLa cells cultured on Matrigel. The short hairpin RNA-mediated knockdown of RhoGDIβ significantly attenuated UVC-induced misorientation. Subsequent expression of wild-type RhoGDIβ, but not a noncleavable mutant, RhoGDIβ (D19A), again led to a relative increase in spindle misorientation in response to UVC. Our findings revealed that RhoGDIβ impacts spindle orientation in response to DNA damage.
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Affiliation(s)
- Natsumi Doi
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
| | - Yuuki Kunimatsu
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
| | - Kouhei Fujiura
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
| | - Hiro Togari
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
| | - Kenji Minagi
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
| | - Koichi Nakaoji
- Research & Development Division, Pias Corporation, Kobe, Japan
| | - Kazuhiko Hamada
- Research & Development Division, Pias Corporation, Kobe, Japan
| | - Achim Temme
- Department of Neurosurgery, University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany
| | - Masaaki Tatsuka
- Department of Life Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shoubara, Hiroshima, Japan
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Pichaud F, Walther RF, Nunes de Almeida F. Regulation of Cdc42 and its effectors in epithelial morphogenesis. J Cell Sci 2019; 132:132/10/jcs217869. [PMID: 31113848 DOI: 10.1242/jcs.217869] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cdc42 - a member of the small Rho GTPase family - regulates cell polarity across organisms from yeast to humans. It is an essential regulator of polarized morphogenesis in epithelial cells, through coordination of apical membrane morphogenesis, lumen formation and junction maturation. In parallel, work in yeast and Caenorhabditis elegans has provided important clues as to how this molecular switch can generate and regulate polarity through localized activation or inhibition, and cytoskeleton regulation. Recent studies have revealed how important and complex these regulations can be during epithelial morphogenesis. This complexity is mirrored by the fact that Cdc42 can exert its function through many effector proteins. In epithelial cells, these include atypical PKC (aPKC, also known as PKC-3), the P21-activated kinase (PAK) family, myotonic dystrophy-related Cdc42 binding kinase beta (MRCKβ, also known as CDC42BPB) and neural Wiskott-Aldrich syndrome protein (N-WASp, also known as WASL). Here, we review how the spatial regulation of Cdc42 promotes polarity and polarized morphogenesis of the plasma membrane, with a focus on the epithelial cell type.
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Affiliation(s)
- Franck Pichaud
- MRC - Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK .,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Rhian F Walther
- MRC - Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
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9
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Oncogenic KRas mobility in the membrane and signaling response. Semin Cancer Biol 2019; 54:109-113. [DOI: 10.1016/j.semcancer.2018.02.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/21/2018] [Accepted: 02/26/2018] [Indexed: 12/12/2022]
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10
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Bruurs LJM, van der Net MC, Zwakenberg S, Zwartkruis FJT, Bos JL. A Tuba/Cdc42/Par6A complex is required to ensure singularity in apical domain formation during enterocyte polarization. PLoS One 2018; 13:e0207159. [PMID: 30408122 PMCID: PMC6224091 DOI: 10.1371/journal.pone.0207159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/25/2018] [Indexed: 01/15/2023] Open
Abstract
Apico-basal polarity establishment is a seminal process in tissue morphogenesis. To function properly it is often imperative that epithelial cells limit apical membrane formation to a single domain. We previously demonstrated that signaling by the small GTPase Cdc42, together with its guanine nucleotide exchange factor (GEF) Tuba, is required to prevent the formation of multiple apical domains in polarized Ls174T:W4 cells, a single cell model for enterocyte polarization. To further chart the molecular signaling mechanisms that safeguard singularity during enterocyte polarization we generated knockout cells for the Cdc42 effector protein Par6A. Par6A loss results in the formation of multiple apical domains, similar to loss of Cdc42. In Par6A knockout cells, we find that active Cdc42 is more mobile at the apical membrane compared to control cells and that wild type Cdc42 is more diffusely localized throughout the cell, indicating that Par6A is required to restrict Cdc42 signaling. Par6A, Cdc42 and its GEF Tuba bind in a co-immunoprecipitation experiment and they partially colocalize at the apical membrane in polarized Ls174T:W4 cells, suggesting the formation of a trimeric complex. Indeed, in a rescue experiment using Par6A mutants, we show that the ability to establish this trimeric complex correlates with the ability to restore singularity in Par6A knockout cells. Together, these experiments therefore indicate that a Tuba/Cdc42/Par6A complex is required to ensure the formation of a single apical domain during enterocyte polarization.
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Affiliation(s)
- Lucas J. M. Bruurs
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Mirjam C. van der Net
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Susan Zwakenberg
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Fried J. T. Zwartkruis
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Johannes L. Bos
- Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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Hapak SM, Ghosh S, Rothlin CV. Axon Regeneration: Antagonistic Signaling Pairs in Neuronal Polarization. Trends Mol Med 2018; 24:615-629. [PMID: 29934283 DOI: 10.1016/j.molmed.2018.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 01/29/2023]
Abstract
Genome-wide screens, proteomics, and candidate-based approaches have identified numerous genes associated with neuronal regeneration following central nervous system (CNS) injury. Despite significant progress, functional recovery remains a challenge, even in model systems. Neuronal function depends on segregation of axonal versus dendritic domains. A key to functional recovery may lie in recapitulating the developmental signals that instruct axon specification and growth in adult neurons post-injury. Theoretically, binary activator-inhibitor elements operating as a Turing-like system within neurons can specify axonal versus dendritic domains and promote axon growth. We review here various molecules implicated in axon specification that function as signaling pairs driving neuronal polarization and axon growth.
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Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN 55455, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT 06511, USA; Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA; Equal contribution.
| | - Carla V Rothlin
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA; Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT 06520, USA; Equal contribution.
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