LIM kinase 1 coordinates microtubule stability and actin polymerization in human endothelial cells.
Microtubule (MT) destabilization promotes the formation of actin stress fibers and enhances the contractility of cells; however, the mechanism involved in the coordinated regulation of MTs and the actin cytoskeleton is poorly understood. LIM kinase 1 (LIMK1) regulates actin polymerization by phosphorylating the actin depolymerization factor, cofilin. Here we report that LIMK1 is also involved in the MT destabilization. In endothelial cells endogenous LIMK1 co-localizes with MTs and forms a complex with tubulin via the PDZ domain. MT destabilization induced by thrombin or nocodazole resulted in a decrease of LIMK1 colocalization with MTs. Overexpression of wild type LIMK1 resulted in MT destabilization, whereas the kinase-dead mutant of LIMK1 (KD) did not affect MT stability. Importantly, down-regulation of endogenous LIMK1 by small interference RNA resulted in abrogation of the thrombin-induced MTs destabilization and the inhibition of thrombin-induced actin polymerization. Expression of Rho kinase 2, which phosphorylates and activates LIMK1, dramatically decreases the interaction of LIMK1 with tubulin but increases its interaction with actin. Interestingly, expression of KD-LIMK1 or small interference RNA-LIMK1 prevents thrombin-induced microtubule destabilization and F-actin formation, suggesting that LIMK1 activity is required for thrombin-induced modulation of microtubule destabilization and actin polymerization. Our findings indicate that LIMK1 may coordinate microtubules and actin cytoskeleton.
Gorovoy
Matvey
M
Department of Pharmacology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA.
Niu
Jiaxin
J
Bernard
Ora
O
Profirovic
Jasmina
J
Minshall
Richard
R
Neamu
Radu
R
Voyno-Yasenetskaya
Tatyana
T
D000199:Actins / Q000737:chemistry*; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins; D054461:Lim Kinases; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D015739:Nocodazole / Q000737:chemistry / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013917:Thrombin / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D014404:Tubulin / Q000737:chemistry; D054460:rho-Associated Kinases
D000199:Actins; D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D014404:Tubulin; D012313:RNA; D004247:DNA; D011494:Protein Kinases; C515892:LIMK1 protein, human; D054461:Lim Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D013917:Thrombin; D015739:Nocodazole