Involvement of Sib Proteins in the Regulation of Cellular Adhesion in
            <i>Dictyostelium discoideum</i>

Cornillon, Sophie; Froquet, Romain Bruno; Cosson, Pierre

doi:10.1128/ec.00155-08

Cited by 34 publications

(43 citation statements)

References 27 publications

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“…During slug migration, the slime sheath is synthesised continuously by pre-stalk cells and serves as a substrate for the outer cells of the slug to move on top of and get traction from. The interaction between the slug outer cells and the slime sheath involves specialised cellmatrix-adhesion molecules of the integrin family, and contacts are organised in focal adhesions that contain talin B and paxillin B (Bukharova et al, 2005;Cornillon et al, 2008;Patel et al, 2008). The sheath is stationary with respect to the substrate on which the slug moves and collapses when the slug has moved through, leaving behind a slime trail (Kessin, 2001).…”

Section: Coordination Of Collective Movement During Dictyostelium Aggmentioning

confidence: 99%

Collective cell migration in development

Weijer

2009

Journal of Cell Science

284

230

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Collective cell migration is a key process during the development of most organisms. It can involve either the migration of closely packed mesenchymal cells that make dynamic contacts with frequently changing neighbour cells, or the migration of epithelial sheets that typically display more stable cell-cell interactions and less frequent changes in neighbours. These collective movements can be controlled by short- or long-range dynamic gradients of extracellular signalling molecules, depending on the number of cells involved and their distance of migration. These gradients are sensed by some or all of the migrating cells and translated into directed migration, which in many settings is further modulated by cell-contact-mediated attractive or repulsive interactions that result in contact-following or contact-inhibition of locomotion, respectively. Studies of collective migration of groups of epithelial cells during development indicate that, in some cases, only leader cells sense and migrate up an external signal gradient, and that adjacent cells follow through strong cell-cell contacts. In this Commentary, I review studies of collective cell migration of differently sized cell populations during the development of several model organisms, and discuss our current understanding of the molecular mechanisms that coordinate this migration.

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Section: Coordination Of Collective Movement During Dictyostelium Aggmentioning

confidence: 99%

Collective cell migration in development

Weijer

2009

Journal of Cell Science

284

230

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“…The Sib proteins are proposed to be functional homologs of the β-chain of integrin heterodimer in Dictyostelium, and talin A binds to all of the five Sib proteins in vitro (18). Specifically, SibA is shown to be important in cellsubstrate adhesion in the unicellular stage (17,18). We produced a double knockout mutant lacking both talin A and SibA (talin A/SibA-null) and found that they seldom produced long tails during chemotactic locomotion (Fig.…”

Section: Talin a Is Required For Normal Tail Retraction In Directed Cellmentioning

confidence: 99%

“…This is consistent with a model in which some adhesion molecules normally linked to the cortical cytoskeleton by talin A are not pulled off the substratum in talin Anull cells that keep advancing. SibA (17,18) is a candidate of such adhesion molecules. The Sib proteins are proposed to be functional homologs of the β-chain of integrin heterodimer in Dictyostelium, and talin A binds to all of the five Sib proteins in vitro (18).…”

Section: Talin a Is Required For Normal Tail Retraction In Directed Cellmentioning

confidence: 99%

Talin couples the actomyosin cortex to the plasma membrane during rear retraction and cytokinesis

Tsujioka

Yumura

Inouye

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Contraction of the cortical actin cytoskeleton underlies both rear retraction in directed cell migration and cytokinesis. Here, we show that talin, a central component of focal adhesions, has a major role in these processes. We found that Dictyostelium talin A colocalized with myosin II in the rear of migrating cells and the cleavage furrow. During directed cell migration, talin A-null cells displayed a long thin tail devoid of actin filaments, whereas additional depletion of SibA, a transmembrane adhesion molecule that binds to talin A, reverted this phenotype, suggesting a requirement of the link between actomyosin and SibA by talin A for rear retraction. Disruptions of talin A also resulted in detachment of the actomyosin contractile ring from the cell membrane and concomitant regression of the cleavage furrow under certain conditions. The C-terminal actin-binding domain (ABD) of talin A exhibited a localization pattern identical to that of full-length talin A. The N-terminal FERM domain was found to bind phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] and phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] in vitro. In vivo, however, PtdIns(4,5)P2, which is known to activate talin, is believed to be enriched in the rear of migrating cells and the cleavage furrow in Dictyostelium . From these results, we propose that talin A activated by PtdIns(4,5)P2 in the cell posterior or cleavage furrow links actomyosin cytoskeleton to adhesion molecules or other membrane proteins, and that the force is transmitted through these links to retract the tail during cell migration or to cause efficient ingression of the equator during cytokinesis.

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“…It is likely that SadA is not the sole mediator of substrate adhesion during the vegetative stage of Dictyostelium amoebae. The Sib (similar to integrin beta) proteins, of which there are five different genes encoded in the genome, are also receptor candidates (9,10). While only two Sib proteins (A and C) are expressed during vegetative growth, all five members have been shown to interact with TalA (Dictyostelium talin homologue), which consequently has also been shown to have a role in substrate adhesion.…”

Section: Vol 10 2011mentioning

confidence: 99%

“…Intriguingly, Dictyostelium encodes a number of homologous proteins that are involved in adhesion in higher eukaryotes, such as talin, Rap1, paxillin, and others (7,21,24,32). Recently, a protein with some attributes of metazoan ␤-integrins was identified in Dictyostelium, but its placement in a cell-substrate adhesion pathway remains to be defined (9,10). These Dictyostelium proteins likewise have documented roles in adhesion.…”

mentioning

confidence: 99%

Uncovering a Role for the Tail of the Dictyostelium discoideum SadA Protein in Cell-Substrate Adhesion

Kowal¹,

Chisholm²

2011

Eukaryotic Cell

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Previous work from our laboratory showed that the Dictyostelium discoideum SadA protein plays a central role in cell-substrate adhesion. SadA null cells exhibit a loss of adhesion, a disrupted actin cytoskeleton, and a cytokinesis defect. How SadA mediates these phenotypes is unknown. This work addresses the mechanism of SadA function, demonstrating an important role for the C-terminal cytoplasmic tail in SadA function. We found that a SadA tailless mutant was unable to rescue the sadA adhesion deficiency, and overexpression of the SadA tail domain reduced adhesion in wild-type cells. We also show that SadA is closely associated with the actin cytoskeleton. Mutagenesis studies suggested that four serine residues in the tail, S924/S925 and S940/ S941, may regulate association of SadA with the actin cytoskeleton. Glutathione S-transferase pull-down assays identified at least one likely interaction partner of the SadA tail, cortexillin I, a known actin bundling protein.Thus, our data demonstrate an important role for the carboxy-terminal cytoplasmic tail in SadA function and strongly suggest that a phosphorylation event in this tail regulates an interaction with cortexillin I. Based on our data, we propose a model for the function of SadA.

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Involvement of Sib Proteins in the Regulation of Cellular Adhesion in Dictyostelium discoideum

Cited by 34 publications

References 27 publications

Collective cell migration in development

Collective cell migration in development

Talin couples the actomyosin cortex to the plasma membrane during rear retraction and cytokinesis

Uncovering a Role for the Tail of the Dictyostelium discoideum SadA Protein in Cell-Substrate Adhesion

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