title: MAPKAPK-2-mediated LIM-kinase activation is critical for VEGF-induced actin remodeling and cell migration.
abstract: Vascular endothelial growth factor-A (VEGF-A) induces actin reorganization and migration of endothelial cells through a p38 mitogen-activated protein kinase (MAPK) pathway. LIM-kinase 1 (LIMK1) induces actin remodeling by phosphorylating and inactivating cofilin, an actin-depolymerizing factor. In this study, we demonstrate that activation of LIMK1 by MAPKAPK-2 (MK2; a downstream kinase of p38 MAPK) represents a novel signaling pathway in VEGF-A-induced cell migration. VEGF-A induced LIMK1 activation and cofilin phosphorylation, and this was inhibited by the p38 MAPK inhibitor SB203580. Although p38 phosphorylated LIMK1 at Ser-310, it failed to activate LIMK1 directly; however, MK2 activated LIMK1 by phosphorylation at Ser-323. Expression of a Ser-323-non-phosphorylatable mutant of LIMK1 suppressed VEGF-A-induced stress fiber formation and cell migration; however, expression of a Ser-323-phosphorylation-mimic mutant enhanced these processes. Knockdown of MK2 by siRNA suppressed VEGF-A-induced LIMK1 activation, stress fiber formation, and cell migration. Expression of kinase-dead LIMK1 suppressed VEGF-A-induced tubule formation. These findings suggest that MK2-mediated LIMK1 phosphorylation/activation plays an essential role in VEGF-A-induced actin reorganization, migration, and tubule formation of endothelial cells.
authors.affiliation: Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Michiru
authors.initials: M
authors.lastname: Nishita
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Mishima
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Ohashi
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mizuno
mesh_terms: D000199:Actins / Q000378:metabolism; D019943:Amino Acid Substitution; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D051338:Cofilin 1 / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D054461:Lim Kinases; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation / Q000187:drug effects; D017354:Point Mutation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000502:physiology; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D014404:Tubulin / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism* / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D000199:Actins; D051338:Cofilin 1; D004791:Enzyme Inhibitors; D007093:Imidazoles; D047908:Intracellular Signaling Peptides and Proteins; D054461:Lim Kinases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines; D034741:RNA, Small Interfering; D014404:Tubulin; D042461:Vascular Endothelial Growth Factor A; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C467484:VEGFA protein, human; C515892:LIMK1 protein, human; C093642:SB 203580