Stromal Cell-Derived Factor 1α Activates LIM Kinase 1 and Induces Cofilin Phosphorylation for T-Cell Chemotaxis

ABSTRACT Stromal cell-derived factor 1 α (SDF-1α), the ligand for G-protein-coupled receptor CXCR4, is a chemotactic factor for T lymphocytes. LIM kinase 1 (LIMK1) phosphorylates cofilin, an actin-depolymerizing and -severing protein, at Ser-3 and regulates actin reorganization. We investigated the role of cofilin phosphorylation by LIMK1 in SDF-1α-induced chemotaxis of T lymphocytes. SDF-1α significantly induced the activation of LIMK1 in Jurkat human leukemic T cells and peripheral blood lymphocytes. SDF-1α also induced cofilin phosphorylation, actin reorganization, and activation of small GTPases, Rho, Rac, and Cdc42, in Jurkat cells. Pretreatment with pertussis toxin inhibited SDF-1α-induced LIMK1 activation, thus indicating that Gi protein is involved in LIMK1 activation. Expression of dominant negative Rac (DN-Rac), but not DN-Rho or DN-Cdc42, blocked SDF-1α-induced activation of LIMK1, which means that SDF-1α-induced LIMK1 activation is mediated by Rac but not by Rho or Cdc42. We used a cell-permeable peptide (S3 peptide) that contains the phosphorylation site (Ser-3) of cofilin to inhibit the cellular function of LIMK1. S3 peptide inhibited the kinase activity of LIMK1 in vitro. Treatment of Jurkat cells with S3 peptide inhibited the SDF-1α-induced cofilin phosphorylation, actin reorganization, and chemotactic response of Jurkat cells. These results suggest that the phosphorylation of cofilin by LIMK1 plays a critical role in the SDF-1α-induced chemotactic response of T lymphocytes.

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Cofilin phosphorylation by LIM-kinase 1 and its role in Rac-mediated actin reorganization

Nature ◽

10.1038/31735 ◽

1998 ◽

Vol 393 (6687) ◽

pp. 809-812 ◽

Cited By ~ 863

Author(s):

Neng Yang ◽

Osamu Higuchi ◽

Kazumasa Ohashi ◽

Kyoko Nagata ◽

Atsushi Wada ◽

...

Keyword(s):

Lim Kinase ◽

Actin Reorganization ◽

Lim Kinase 1 ◽

Cofilin Phosphorylation

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Hyperosmotic stress induces Rho/Rho kinase/LIM kinase-mediated cofilin phosphorylation in tubular cells: key role in the osmotically triggered F-actin response

AJP Cell Physiology ◽

10.1152/ajpcell.00467.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. C463-C475 ◽

Cited By ~ 45

Author(s):

Ana C. P. Thirone ◽

Pam Speight ◽

Matthew Zulys ◽

Ori D. Rotstein ◽

Katalin Szászi ◽

...

Keyword(s):

Actin Polymerization ◽

De Novo ◽

Rho Kinase ◽

Small Gtpases ◽

Hyperosmotic Stress ◽

Dominant Negative ◽

Lim Kinase ◽

Tubular Cells ◽

Cofilin Phosphorylation ◽

Underlying Mechanisms

Hyperosmotic stress induces cytoskeleton reorganization and a net increase in cellular F-actin, but the underlying mechanisms are incompletely understood. Whereas de novo F-actin polymerization likely contributes to the actin response, the role of F-actin severing is unknown. To address this problem, we investigated whether hyperosmolarity regulates cofilin, a key actin-severing protein, the activity of which is inhibited by phosphorylation. Since the small GTPases Rho and Rac are sensitive to cell volume changes and can regulate cofilin phosphorylation, we also asked whether they might link osmostress to cofilin. Here we show that hyperosmolarity induced rapid, sustained, and reversible phosphorylation of cofilin in kidney tubular (LLC-PK1 and Madin-Darby canine kidney) cells. Hyperosmolarity-provoked cofilin phosphorylation was mediated by the Rho/Rho kinase (ROCK)/LIM kinase (LIMK) but not the Rac/PAK/LIMK pathway, because 1) dominant negative (DN) Rho and DN-ROCK but not DN-Rac and DN-PAK inhibited cofilin phosphorylation; 2) constitutively active (CA) Rho and CA-ROCK but not CA-Rac and CA-PAK induced cofilin phosphorylation; 3) hyperosmolarity induced LIMK-2 phosphorylation, and 4) inhibition of ROCK by Y-27632 suppressed the hypertonicity-triggered LIMK-2 and cofilin phosphorylation.We thenexamined whether cofilin and its phosphorylation play a role in the hypertonicity-triggered F-actin changes. Downregulation of cofilin by small interfering RNA increased the resting F-actin level and eliminated any further rise upon hypertonic treatment. Inhibition of cofilin phosphorylation by Y-27632 prevented the hyperosmolarity-provoked F-actin increase. Taken together, cofilin is necessary for maintaining the osmotic responsiveness of the cytoskeleton in tubular cells, and the Rho/ROCK/LIMK-mediated cofilin phosphorylation is a key mechanism in the hyperosmotic stress-induced F-actin increase.

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Parkin interacts with LIM Kinase 1 and reduces its cofilin-phosphorylation activity via ubiquitination

Experimental Cell Research ◽

10.1016/j.yexcr.2007.04.016 ◽

2007 ◽

Vol 313 (13) ◽

pp. 2858-2874 ◽

Cited By ~ 51

Author(s):

Meng K. Lim ◽

Takeshi Kawamura ◽

Yosuke Ohsawa ◽

Masafumi Ohtsubo ◽

Shuichi Asakawa ◽

...

Keyword(s):

Lim Kinase ◽

Lim Kinase 1 ◽

Cofilin Phosphorylation

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Regulation of LIM-kinase 1 and cofilin in thrombin-stimulated platelets

Blood ◽

10.1182/blood-2004-11-4377 ◽

2006 ◽

Vol 107 (2) ◽

pp. 575-583 ◽

Cited By ~ 39

Author(s):

Dharmendra Pandey ◽

Pankaj Goyal ◽

James R. Bamburg ◽

Wolfgang Siess

Keyword(s):

Shape Change ◽

Rho Kinase ◽

Lim Kinase ◽

Kinase Activation ◽

Integrin Αiibβ3 ◽

Lim Kinase 1 ◽

Filament Dynamics ◽

Cofilin Phosphorylation ◽

High Concentrations ◽

Platelet Shape

Abstract Cofilin is a regulator of actin filament dynamics. We studied whether during platelet activation Rho kinase stimulates LIM kinase (LIMK) leading to subsequent phosphorylation and inactivation of cofilin. Platelet shape change and aggregation/secretion were induced by low and high concentrations of thrombin, respectively. We found that during these platelet responses Rho kinase activation was responsible for mediating rapid Thr508 phosphorylation and activation of LIMK-1 and for the F-actin increase during shape change and, in part, during secretion. Surprisingly, during shape change cofilin phosphorylation was unaltered, and during aggregation/secretion cofilin was first rapidly dephosphorylated by an okadaic acid–insensitive phosphatase and then slowly rephosphorylated by LIMK-1. LIMK-1 phosphorylation and cofilin dephosphorylation and rephosphorylation during aggregation were independent of integrin αIIbβ3 engagement. Cofilin phosphorylation did not regulate cofilin association with F-actin and was unrelated to the F-actin increase in thrombin-activated platelets. Our study identifies LIMK-1 as being activated by Rho kinase in thrombin-stimulated platelets. Two counteracting pathways, a cofilin phosphatase and LIMK-1, are activated during platelet aggregation/secretion regulating cofilin phosphorylation sequentially and independently of integrin αIIbβ3 engagement. Rho kinase–mediated F-actin increase during platelet shape change and secretion involves a mechanism other than LIMK-1–mediated cofilin phosphorylation, raising the possibility of another LIMK substrate regulating platelet actin assembly.

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