scholarly journals MYADM regulates Rac1 targeting to ordered membranes required for cell spreading and migration

2011 ◽  
Vol 22 (8) ◽  
pp. 1252-1262 ◽  
Author(s):  
Juan F. Aranda ◽  
Natalia Reglero-Real ◽  
Leonor Kremer ◽  
Beatriz Marcos-Ramiro ◽  
Ana Ruiz-Sáenz ◽  
...  

Membrane organization into condensed domains or rafts provides molecular platforms for selective recruitment of proteins. Cell migration is a general process that requires spatiotemporal targeting of Rac1 to membrane rafts. The protein machinery responsible for making rafts competent to recruit Rac1 remains elusive. Some members of the MAL family of proteins are involved in specialized processes dependent on this type of membrane. Because condensed membrane domains are a general feature of the plasma membrane of all mammalian cells, we hypothesized that MAL family members with ubiquitous expression and plasma membrane distribution could be involved in the organization of membranes for cell migration. We show that myeloid-associated differentiation marker (MYADM), a protein with unique features within the MAL family, colocalizes with Rac1 in membrane protrusions at the cell surface and distributes in condensed membranes. MYADM knockdown (KD) cells had altered membrane condensation and showed deficient incorporation of Rac1 to membrane raft fractions and, similar to Rac1 KD cells, exhibited reduced cell spreading and migration. Results of rescue-of-function experiments by expression of MYADM or active Rac1L61 in cells knocked down for Rac1 or MYADM, respectively, are consistent with the idea that MYADM and Rac1 act on parallel pathways that lead to similar functional outcomes.

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Onur Cizmecioglu ◽  
Jing Ni ◽  
Shaozhen Xie ◽  
Jean J Zhao ◽  
Thomas M Roberts

We aimed to understand how spatial compartmentalization in the plasma membrane might contribute to the functions of the ubiquitous class IA phosphoinositide 3-kinase (PI3K) isoforms, p110α and p110β. We found that p110β localizes to membrane rafts in a Rac1-dependent manner. This localization potentiates Akt activation by G-protein-coupled receptors (GPCRs). Thus genetic targeting of a Rac1 binding-deficient allele of p110β to rafts alleviated the requirement for p110β-Rac1 association for GPCR signaling, cell growth and migration. In contrast, p110α, which does not play a physiological role in GPCR signaling, is found to reside in nonraft regions of the plasma membrane. Raft targeting of p110α allowed its EGFR-mediated activation by GPCRs. Notably, p110β dependent, PTEN null tumor cells critically rely upon raft-associated PI3K activity. Collectively, our findings provide a mechanistic account of how membrane raft localization regulates differential activation of distinct PI3K isoforms and offer insight into why PTEN-deficient cancers depend on p110β.


2013 ◽  
Vol 452 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Mark Willett ◽  
Michele Brocard ◽  
Hilary J. Pollard ◽  
Simon J. Morley

During cell spreading, mammalian cells migrate using lamellipodia formed from a large dense branched actin network which produces the protrusive force required for leading edge advancement. The formation of lamellipodia is a dynamic process and is dependent on a variety of protein cofactors that mediate their local regulation, structural characteristics and dynamics. In the present study, we show that mRNAs encoding some structural and regulatory components of the WAVE [WASP (Wiskott–Aldrich syndrome protein) verprolin homologous] complex are localized to the leading edge of the cell and associated with sites of active translation. Furthermore, we demonstrate that steady-state levels of ArpC2 and Rac1 proteins increase at the leading edge during cell spreading, suggesting that localized protein synthesis has a pivotal role in controlling cell spreading and migration.


1996 ◽  
Vol 109 (6) ◽  
pp. 1615-1622 ◽  
Author(s):  
E.J. Filardo ◽  
S.L. Deming ◽  
D.A. Cheresh

CS-1 melanoma cells transfected with cDNAs encoding either the beta 3 or beta 5 integrin subunit protein express alpha v beta 3 or alpha v beta 5, respectively, enabling them to adhere to vitronectin yet only alpha v beta 3 promotes cell spreading and migration on this substrate. Following exposure to insulin or insulin-like growth factor, alpha v beta 5-expressing CS-1 cells gain the ability to migrate on vitronectin. To identify structural regions in beta 3 or beta 5 that account for these distinct biological properties, CS-1 cells were transfected with one of two chimeric beta subunit proteins, in which the ecto- and cytoplasmic domains of beta 3 and beta 5 were exchanged (termed alpha v beta 3/5 or alpha v beta 5/3). Surprisingly, alpha v beta 3/5 expressing cells spread and migrate on vitronectin while cells expressing alpha v beta 5/3 do not unless they are exposed to cytokine. These findings suggest that the distinct migratory properties mediated by integrins alpha v beta 3 and alpha v beta 5 and their response to cytokine activation is determined by a sequence(s) within the ectodomain of the integrin beta subunit.


2008 ◽  
Vol 19 (7) ◽  
pp. 3111-3123 ◽  
Author(s):  
Young Chan Chae ◽  
Jung Hwan Kim ◽  
Kyung Lock Kim ◽  
Hyun Wook Kim ◽  
Hye Young Lee ◽  
...  

Small GTPase Rac is a crucial regulator of actin cytoskeletal rearrangement, and it plays an important role in cell spreading, migration, mitogenesis, phagocytosis, superoxide generation, and axonal growth. It is generally accepted that Rac activity is regulated by the guanosine triphosphate (GTP)/guanosine diphosphate (GDP) cycle. But, it is suggested that in addition to Rac-GTP loading, membrane localization is required for the initiation of downstream effector signaling. However, the molecular mechanisms that control the targeting of GTP-Rac to the plasma membrane remain largely unknown. Here, we have uncovered a signaling pathway linking phospholipase D (PLD) to the localized functions of Rac1. We show that PLD product phosphatidic acid (PA) acts as a membrane anchor of Rac1. The C-terminal polybasic motif of Rac1 is responsible for direct interaction with PA, and Rac1 mutated in this region is incapable of translocating to the plasma membrane and of activating downstream target p21-activated kinase upon integrin activation. Finally, we show that PA induces dissociation of Rho-guanine nucleotide dissociation inhibitor from Rac1 and that PA-mediated Rac1 localization is important for integrin-mediated lamellipodia formation, cell spreading, and migration. These results provide a novel molecular mechanism for the GTP-Rac1 localization through the elevating PLD activity, and they suggest a general mechanism for diverse cellular functions that is required localized Rac activation.


2017 ◽  
Vol 216 (11) ◽  
pp. 3437-3439
Author(s):  
Laura Machesky ◽  
Vania M.M. Braga

Epithelial cells in tissues use their actin cytoskeletons to stick together, whereas unattached cells make active plasma membrane protrusions to migrate. In this issue, Wood et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201612006) show that the junction component α-catenin is critical in freely moving cells to promote adhesion and migration.


Science ◽  
2020 ◽  
Vol 368 (6496) ◽  
pp. 1205-1210 ◽  
Author(s):  
Anjali Bisaria ◽  
Arnold Hayer ◽  
Damien Garbett ◽  
Daniel Cohen ◽  
Tobias Meyer

Cell migration is driven by local membrane protrusion through directed polymerization of F-actin at the front. However, F-actin next to the plasma membrane also tethers the membrane and thus resists outgoing protrusions. Here, we developed a fluorescent reporter to monitor changes in the density of membrane-proximal F-actin (MPA) during membrane protrusion and cell migration. Unlike the total F-actin concentration, which was high in the front of migrating cells, MPA density was low in the front and high in the back. Back-to-front MPA density gradients were controlled by higher cofilin-mediated turnover of F-actin in the front. Furthermore, nascent membrane protrusions selectively extended outward from areas where MPA density was reduced. Thus, locally low MPA density directs local membrane protrusions and stabilizes cell polarization during cell migration.


Author(s):  
Santosh Kumar Sahu ◽  
Himadri Gourav Behuria ◽  
Sangam Gupta ◽  
Babita Sahoo

In an attempt to identify the metal sensing proteins localized to mammalian plasma membrane, the authors screened a list of 300 raft associated proteins that are involved in cellular signaling mechanisms by searching the presence of metal thionin (CXXC) motifs. 50 proteins were found to possess CXXC motifs that could act as potential metal sensing proteins. The authors determined membrane topologies of the above CXXC motif containing proteins using TM-pred and analyzed the positions of their transmembrane (TM) domains using Bio-edit software. Based on the topology of CXXC domains, the authors classified all the raft-associated metal sensing proteins into six categories. They are (i) Exoplasmic tails with CXXC motif, (ii) Exoplasmic loops with CXXC motif, (iii) Cytosolic tails with CXXC motif, (iv) Cytosolic loop with CXXC motif, (v) TM domains with CXXC motifs, (vi) Proteins with multiple topologies of CXXC motif. The authors' study will lead to understanding of the raft-mediated mechanism of heavy metal sensing and signaling in mammalian cells.


2012 ◽  
Vol 199 (2) ◽  
pp. 331-345 ◽  
Author(s):  
Shujie Wang ◽  
Takashi Watanabe ◽  
Kenji Matsuzawa ◽  
Akira Katsumi ◽  
Mai Kakeno ◽  
...  

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Damien Garbett ◽  
Anjali Bisaria ◽  
Changsong Yang ◽  
Dannielle G. McCarthy ◽  
Arnold Hayer ◽  
...  

Abstract Migrating cells move across diverse assemblies of extracellular matrix (ECM) that can be separated by micron-scale gaps. For membranes to protrude and reattach across a gap, actin filaments, which are relatively weak as single filaments, must polymerize outward from adhesion sites to push membranes towards distant sites of new adhesion. Here, using micropatterned ECMs, we identify T-Plastin, one of the most ancient actin bundling proteins, as an actin stabilizer that promotes membrane protrusions and enables bridging of ECM gaps. We show that T-Plastin widens and lengthens protrusions and is specifically enriched in active protrusions where F-actin is devoid of non-muscle myosin II activity. Together, our study uncovers critical roles of the actin bundler T-Plastin to promote protrusions and migration when adhesion is spatially-gapped.


2002 ◽  
Vol 115 (15) ◽  
pp. 3105-3117 ◽  
Author(s):  
Jocelyn Laporte ◽  
Francois Blondeau ◽  
Anne Gansmuller ◽  
Yves Lutz ◽  
Jean-Luc Vonesch ◽  
...  

Myotubularin, the phosphatase mutated in X-linked myotubular myopathy, was shown to dephosphorylate phosphatidylinositol 3-monophosphate(PtdIns3P) and was also reported to interact with nuclear transcriptional regulators from the trithorax family. We have characterized a panel of specific antibodies and investigated the subcellular localization of myotubularin. Myotubularin is not detected in the nucleus, and localizes mostly as a dense cytoplasmic network. Overexpression of myotubularin does not detectably affect vesicle trafficking in the mammalian cells investigated, in contrast to previous observations in yeast models. Both mutation of a key aspartate residue of myotubularin and dominant activation of Rac1 GTPase lead to the recruitment of myotubularin to specific plasma membrane domains. Localization to Rac1-induced ruffles is dependent on the presence of a domain highly conserved in the myotubularin family (that we named RID). We thus propose that myotubularin may dephosphorylate a subpool of PtdIns3P(or another related substrate) at the plasma membrane.


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