Paxillin-kinase-linker tyrosine phosphorylation regulates directional cell migration.
Directed cell migration requires the coordination of growth factor and cell adhesion signaling and is of fundamental importance during embryonic development, wound repair, and pathological conditions such as tumor metastasis. Herein, we demonstrate that the ArfGAP, paxillin-kinase-linker (PKL/GIT2), is tyrosine phosphorylated in response to platelet-derived growth factor (PDGF) stimulation, in an adhesion dependent manner and is necessary for directed cell migration. Using a combination of pharmacological inhibitors, knockout cells and kinase mutants, FAK, and Src family kinases were shown to mediate PDGF-dependent PKL tyrosine phosphorylation. In fibroblasts, expression of a PKL mutant lacking the principal tyrosine phosphorylation sites resulted in loss of wound-induced cell polarization as well as directional migration. PKL phosphorylation was necessary for PDGF-stimulated PKL binding to the focal adhesion protein paxillin and expression of paxillin or PKL mutants defective in their respective binding motifs recapitulated the polarization defects. RNA interference or expression of phosphorylation mutants of PKL resulted in disregulation of PDGF-stimulated Rac1 and PAK activities, reduction of Cdc42 and Erk signaling, as well as mislocalization of betaPIX. Together these studies position PKL as an integral component of growth factor and cell adhesion cross-talk signaling, controlling the development of front-rear cell polarity and directional cell migration.
Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
Jianxin A
JA
Yu
Nicholas O
NO
Deakin
Christopher E
CE
Turner
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D020690:GTPase-Activating Proteins; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; C120767:Git2 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D011993:Recombinant Fusion Proteins; D014443:Tyrosine; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein