Actin dynamics in cell migration

Abstract Cell migration is an essential process, both in unicellular organisms such as amoeba and as individual or collective motility in highly developed multicellular organisms like mammals. It is controlled by a variety of activities combining protrusive and contractile forces, normally generated by actin filaments. Here, we summarize actin filament assembly and turnover processes, and how respective biochemical activities translate into different protrusion types engaged in migration. These actin-based plasma membrane protrusions include actin-related protein 2/3 complex-dependent structures such as lamellipodia and membrane ruffles, filopodia as well as plasma membrane blebs. We also address observed antagonisms between these protrusion types, and propose a model – also inspired by previous literature – in which a complex balance between specific Rho GTPase signaling pathways dictates the protrusion mechanism employed by cells. Furthermore, we revisit published work regarding the fascinating antagonism between Rac and Rho GTPases, and how this intricate signaling network can define cell behavior and modes of migration. Finally, we discuss how the assembly of actin filament networks can feed back onto their regulators, as exemplified for the lamellipodial factor WAVE regulatory complex, tightly controlling accumulation of this complex at specific subcellular locations as well as its turnover.

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Plasma membrane nano-organization specifies phosphoinositide effects on Rho-GTPases and actin dynamics in tobacco pollen tubes

10.1101/2020.08.12.248419 ◽

2020 ◽

Cited By ~ 1

Author(s):

Marta Fratini ◽

Praveen Krishnamoorthy ◽

Irene Stenzel ◽

Mara Riechmann ◽

Kirsten Bacia ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Trafficking ◽

Rho Gtpases ◽

Rho Gtpase ◽

Pollen Tubes ◽

Actin Dynamics ◽

Tobacco Pollen ◽

Dual Distribution ◽

Cytoskeletal Dynamics

AbstractPollen tube growth requires coordination of cytoskeletal dynamics and apical secretion. The regulatory phospholipid, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is enriched in the subapical plasma membrane of pollen tubes and can influence both actin dynamics and secretion. How alternative PtdIns(4,5)P2-effects are specified is unclear. Spinning disc microscopy (SD) reveals dual distribution of a fluorescent PtdIns(4,5)P2-reporter in dynamic plasma membrane nanodomains vs. apparent diffuse membrane labelling, consistent with spatially distinct coexisting pools of PtdIns(4,5)P2. Several PI4P 5-kinases (PIP5Ks) can generate PtdIns(4,5)P2 in pollen tubes. Despite localizing to one membrane region, AtPIP5K2 and NtPIP5K6 display distinctive overexpression effects on cell morphologies, respectively related to altered actin dynamics or membrane trafficking. When analyzed by SD, AtPIP5K2-EYFP associated with nanodomains, whereas NtPIP5K6-EYFP localized diffusely. Chimeric AtPIP5K2 and NtPIP5K6 variants with reciprocally swapped membrane-associating domains evoked reciprocally shifted effects on cell morphology upon overexpression. Overall, PI4P 5-kinase variants targeted to nanodomains stabilized actin, suggesting a specific function of PtdIns(4,5)P2-nanodomains. A distinct role of nanodomain-associated AtPIP5K2 in actin regulation is further supported by proximity to and interaction with the Rho-GTPase NtRac5, and by functional interplay with elements of ROP-signalling. Plasma membrane nano-organization may thus aid the specification of PtdIns(4,5)P2-functions to coordinate cytoskeletal dynamics and secretion in pollen tubes.

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RhoD regulates cytoskeletal dynamics via the actin nucleation–promoting factor WASp homologue associated with actin Golgi membranes and microtubules

Molecular Biology of the Cell ◽

10.1091/mbc.e12-07-0555 ◽

2012 ◽

Vol 23 (24) ◽

pp. 4807-4819 ◽

Cited By ~ 33

Author(s):

Annica K. B. Gad ◽

Vishal Nehru ◽

Aino Ruusala ◽

Pontus Aspenström

Keyword(s):

Cell Migration ◽

Actin Filament ◽

Rho Gtpases ◽

Actin Dynamics ◽

Filamin A ◽

Actin Nucleation ◽

Cellular Processes ◽

Golgi Membranes ◽

Cytoskeletal Dynamics ◽

Nucleation Promoting Factor

The Rho GTPases have mainly been studied in association with their roles in the regulation of actin filament organization. These studies have shown that the Rho GTPases are essential for basic cellular processes, such as cell migration, contraction, and division. In this paper, we report that RhoD has a role in the organization of actin dynamics that is distinct from the roles of the better-studied Rho members Cdc42, RhoA, and Rac1. We found that RhoD binds the actin nucleation–promoting factor WASp homologue associated with actin Golgi membranes and microtubules (WHAMM), as well as the related filamin A–binding protein FILIP1. Of these two RhoD-binding proteins, WHAMM was found to bind to the Arp2/3 complex, while FILIP1 bound filamin A. WHAMM was found to act downstream of RhoD in regulating cytoskeletal dynamics. In addition, cells treated with small interfering RNAs for RhoD and WHAMM showed increased cell attachment and decreased cell migration. These major effects on cytoskeletal dynamics indicate that RhoD and its effectors control vital cytoskeleton-driven cellular processes. In agreement with this notion, our data suggest that RhoD coordinates Arp2/3-dependent and FLNa-dependent mechanisms to control the actin filament system, cell adhesion, and cell migration.

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Regulation of Rho GTPases by RhoGDIs in Human Cancers

Cells ◽

10.3390/cells8091037 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1037 ◽

Cited By ~ 6

Author(s):

Cho ◽

Kim ◽

Baek ◽

Kim ◽

Lee

Keyword(s):

Cell Migration ◽

Cancer Progression ◽

Anticancer Agents ◽

Rho Gtpases ◽

Rho Gtpase ◽

Regulatory Mechanisms ◽

Malignant Phenotype ◽

Cellular Processes ◽

Human Cancers

Rho GDP dissociation inhibitors (RhoGDIs) play important roles in various cellular processes, including cell migration, adhesion, and proliferation, by regulating the functions of the Rho GTPase family. Dissociation of Rho GTPases from RhoGDIs is necessary for their spatiotemporal activation and is dynamically regulated by several mechanisms, such as phosphorylation, sumoylation, and protein interaction. The expression of RhoGDIs has changed in many human cancers and become associated with the malignant phenotype, including migration, invasion, metastasis, and resistance to anticancer agents. Here, we review how RhoGDIs control the function of Rho GTPases by regulating their spatiotemporal activity and describe the regulatory mechanisms of the dissociation of Rho GTPases from RhoGDIs. We also discuss the role of RhoGDIs in cancer progression and their potential uses for therapeutic intervention.

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Selectivity of Guanine Nucleotide Exchange Factor-mediated Cdc42 activation in primary human endothelial cells

10.1101/541219 ◽

2019 ◽

Author(s):

Nathalie R. Reinhard ◽

Sanne van der Niet ◽

Anna Chertkova ◽

Marten Postma ◽

Peter L. Hordijk ◽

...

Keyword(s):

Endothelial Cells ◽

Single Cell ◽

Rho Gtpases ◽

Rho Gtpase ◽

Actin Dynamics ◽

Pleckstrin Homology Domain ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Guanine Nucleotide Exchange ◽

Dh Domain

AbstractThe Rho GTPase family is involved in actin dynamics and regulates the barrier function of the endothelium. One of the main barrier-promoting Rho GTPases is Cdc42, also known as cell division control protein 42 homolog. Currently, regulation of Cdc42-based signaling networks in endothelial cells (ECs) lack molecular details. To examine these, we focused on a subset of 15 Rho guanine nucleotide exchange factors (GEFs), which are expressed in the endothelium. By performing single cell FRET measurements with Rho GTPase biosensors in primary human ECs, we monitored GEF efficiency towards Cdc42 and Rac1. A new, single cell-based analysis was developed and used to enable the quantitative comparison of cellular activities of the full-length GEFs. Our data reveal a specific GEF dependent activation profile, with most efficient Cdc42 activation induced by PLEKHG2, FGD1, PLEKHG1 and pRex1 and the highest selectivity for FGD1. Additionally, we generated truncated GEF constructs that comprise only the catalytic dbl homology (DH) domain or together with the adjacent pleckstrin homology domain (DHPH). The DH domain by itself did not activate Cdc42, whereas the DHPH domain of ITSN1, ITSN2 and PLEKHG1 showed activity towards Cdc42. Together, our study characterized endothelial GEFs that may activate Cdc42, which will be of great value for the field of vascular biology.Abstract FigureGraphical Abstract

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MicroRNA Regulation of the Small Rho GTPase Regulators—Complexities and Opportunities in Targeting Cancer Metastasis

Cancers ◽

10.3390/cancers12051092 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1092 ◽

Cited By ~ 2

Author(s):

Brock A. Humphries ◽

Zhishan Wang ◽

Chengfeng Yang

Keyword(s):

Transcriptional Activation ◽

Rho Gtpases ◽

Cancer Metastasis ◽

Rho Gtpase ◽

Critical Role ◽

Large Family ◽

Actin Dynamics ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Guanine Nucleotide Exchange

The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.

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Activated Ezrin Promotes Cell Migration through Recruitment of the GEF Dbl to Lipid Rafts and Preferential Downstream Activation of Cdc42

Molecular Biology of the Cell ◽

10.1091/mbc.e06-11-1031 ◽

2007 ◽

Vol 18 (8) ◽

pp. 2935-2948 ◽

Cited By ~ 72

Author(s):

Soren Prag ◽

Maddy Parsons ◽

Melanie D. Keppler ◽

Simon M. Ameer-Beg ◽

Paul Barber ◽

...

Keyword(s):

Plasma Membrane ◽

Cell Migration ◽

Lipid Raft ◽

Rho Gtpase ◽

Actin Binding ◽

Fluorescence Lifetime Imaging ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Guanine Nucleotide Exchange ◽

Lipid Raft Microdomains

Establishment of polarized cell morphology is a critical factor for migration and requires precise spatial and temporal activation of the Rho GTPases. Here, we describe a novel role of the actin-binding ezrin/radixin/moesin (ERM)-protein ezrin to be involved in recruiting Cdc42, but not Rac1, to lipid raft microdomains, as well as the subsequent activation of this Rho GTPase and the downstream effector p21-activated kinase (PAK)1, as shown by fluorescence lifetime imaging microscopy. The establishment of a leading plasma membrane and the polarized morphology necessary for random migration are also dependent on ERM function and Cdc42 in motile breast carcinoma cells. Mechanistically, we show that the recruitment of the ERM-interacting Rho/Cdc42-specific guanine nucleotide exchange factor Dbl to the plasma membrane and to lipid raft microdomains requires the phosphorylated, active conformer of ezrin, which serves to tether the plasma membrane or its subdomains to the cytoskeleton. Together these data suggest a mechanism whereby precise spatial guanine nucleotide exchange of Cdc42 by Dbl is dependent on functional ERM proteins and is important for directional cell migration.

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Grit, a GTPase-Activating Protein for the Rho Family, Regulates Neurite Extension through Association with the TrkA Receptor and N-Shc and CrkL/Crk Adapter Molecules

Molecular and Cellular Biology ◽

10.1128/mcb.22.24.8721-8734.2002 ◽

2002 ◽

Vol 22 (24) ◽

pp. 8721-8734 ◽

Cited By ~ 70

Author(s):

Takeshi Nakamura ◽

Misako Komiya ◽

Kiyoaki Sone ◽

Eiji Hirose ◽

Noriko Gotoh ◽

...

Keyword(s):

Tyrosine Kinases ◽

Rho Gtpases ◽

Rho Gtpase ◽

Neuronal Cells ◽

Small Gtpases ◽

Actin Dynamics ◽

Gtpase Activating Protein ◽

Interacting Protein ◽

High Affinity Receptor ◽

Rho Family

ABSTRACT Neurotrophins are key regulators of the fate and shape of neuronal cells and act as guidance cues for growth cones by remodeling the actin cytoskeleton. Actin dynamics is controlled by Rho GTPases. We identified a novel Rho GTPase-activating protein (Grit) for Rho/Rac/Cdc42 small GTPases. Grit was abundant in neuronal cells and directly interacted with TrkA, a high-affinity receptor for nerve growth factor (NGF). Another pool of Grit was recruited to the activated receptor tyrosine kinase through its binding to N-Shc and CrkL/Crk, adapter molecules downstream of activated receptor tyrosine kinases. Overexpression of the TrkA-binding region of Grit inhibited NGF-induced neurite elongation. Further, we found some tendency for neurite promotion in full-length Grit-overexpressing PC12 cells upon NGF stimulation. These results suggest that Grit, a novel TrkA-interacting protein, regulates neurite outgrowth by modulating the Rho family of small GTPases.

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The RhoGAP myosin 9/HUM-7 integrates membrane signals to modulate Rho/RHO-1 during embryonic morphogenesis in C. elegans

10.1101/325274 ◽

2018 ◽

Cited By ~ 1

Author(s):

Andre G. Wallace ◽

Hamidah Raduwan ◽

John Carlet ◽

Martha C. Soto

Keyword(s):

Plasma Membrane ◽

Epidermal Cell ◽

Rho Gtpase ◽

Actin Dynamics ◽

Rac Gtpase ◽

Cell Behaviors ◽

C Elegans ◽

Embryonic Morphogenesis

AbstractDuring embryonic morphogenesis, cells and tissues undergo dramatic movements under the control of F-actin regulators. Our studies of epidermal cell migrations in developing C. elegans embryos have identified multiple plasma membrane signals that regulate the Rac GTPase, thus regulating WAVE and Arp2/3 complexes, to promote branched F-actin formation and polarized enrichment. We describe here a pathway that acts in parallel to Rac to transduce membrane signals to control epidermal F-actin through the GTPase Rho. Rho contributes to epidermal migrations through effects on underlying neuroblasts. Here we identify signals to regulate Rho in the epidermis. HUM-7, the C. elegans homolog of human Myo9A and Myo9B, regulates F-actin dynamics during epidermal migrations, by controlling Rho. Genetics and biochemistry support that HUM-7 behaves as GAP for the Rho GTPase, so that loss of HUM-7 enhances Rho-dependent epidermal cell behaviors. We identify SAX-3/ROBO as an upstream signal that contributes to attenuated Rho activation through its regulation of HUM-7/Myo9. These studies identify a new role for Rho during epidermal cell migrations, and suggest that Rho activity is regulated by SAX-3/ROBO acting on the RhoGAP HUM-7.

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Mechanochemical coupling and junctional forces during collective cell migration

10.1101/558452 ◽

2019 ◽

Author(s):

J. Bui ◽

D. E. Conway ◽

R. L. Heise ◽

S.H. Weinberg

Keyword(s):

Cell Migration ◽

Rho Gtpases ◽

Cancer Metastasis ◽

Rho Gtpase ◽

Critical Role ◽

Leading Edge ◽

Collective Cell Migration ◽

Gtpase Activity ◽

Modeling Framework ◽

Cell Cell

ABSTRACTCell migration, a fundamental physiological process in which cells sense and move through their surrounding physical environment, plays a critical role in development and tissue formation, as well as pathological processes, such as cancer metastasis and wound healing. During cell migration, dynamics are governed by the bidirectional interplay between cell-generated mechanical forces and the activity of Rho GTPases, a family of small GTP-binding proteins that regulate actin cytoskeleton assembly and cellular contractility. These interactions are inherently more complex during the collective migration of mechanically coupled cells, due to the additional regulation of cell-cell junctional forces. In this study, we present a minimal modeling framework to simulate the interactions between mechanochemical signaling in individual cells and interactions with cell-cell junctional forces during collective cell migration. We find that migration of individual cells depends on the feedback between mechanical tension and Rho GTPase activity in a biphasic manner. During collective cell migration, waves of Rho GTPase activity mediate mechanical contraction/extension and thus synchronization throughout the tissue. Further, cell-cell junctional forces exhibit distinct spatial patterns during collective cell migration, with larger forces near the leading edge. Larger junctional force magnitudes are associated with faster collective cell migration and larger tissue size. Simulations of heterogeneous tissue migration exhibit a complex dependence on the properties of both leading and trailing cells. Computational predictions demonstrate that collective cell migration depends on both the emergent dynamics and interactions between cellular-level Rho GTPase activity and contractility, and multicellular-level junctional forces.

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Functional and Therapeutic Relevance of Rho GTPases in Innate Immune Cell Migration and Function during Inflammation: An In Silico Perspective

Mediators of Inflammation ◽

10.1155/2021/6655412 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Pankaj Dipankar ◽

Puneet Kumar ◽

Shiba Prasad Dash ◽

Pranita P. Sarangi

Keyword(s):

Cell Migration ◽

Immune Cells ◽

Rho Gtpases ◽

Inflammatory Cell ◽

Immune Cell ◽

Rho Gtpase ◽

Innate Immune ◽

Molecular Organization ◽

Exchange Reactions ◽

And Function

Systematic regulation of leukocyte migration to the site of infection is a vital step during immunological responses. Improper migration and localization of immune cells could be associated with disease pathology as seen in systemic inflammation. Rho GTPases act as molecular switches during inflammatory cell migration by cycling between Rho-GDP (inactive) to Rho-GTP (active) forms and play an essential role in the precise regulation of actin cytoskeletal dynamics as well as other immunological functions of leukocytes. Available reports suggest that the dysregulation of Rho GTPase signaling is associated with various inflammatory diseases ranging from mild to life-threatening conditions. Therefore, it is crucial to understand the step-by-step activation and inactivation of GTPases and the functioning of different Guanine Nucleotide Exchange Factors (GEFs) and GTPase-Activating Proteins (GAPs) that regulate the conversion of GDP to GTP and GTP to GDP exchange reactions, respectively. Here, we describe the molecular organization and activation of various domains of crucial elements associated with the activation of Rho GTPases using solved PDB structures. We will also present the latest evidence available on the relevance of Rho GTPases in the migration and function of innate immune cells during inflammation. This knowledge will help scientists design promising drug candidates against the Rho-GTPase-centric regulatory molecules regulating inflammatory cell migration.

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