Protein kinase A-dependent increase in WAVE2 expression induced by the focal adhesion protein vinexin.
The focal adhesion protein vinexin is a member of a family of adaptor proteins that are thought to participate in the regulation of cell adhesion, cytoskeletal reorganization, and growth factor signaling. Here, we show that vinexin beta increases the amount of and reduces the mobility on SDS-PAGE of Wiskott-Aldrich syndrome protein family verprolin-homologous protein (WAVE) 2 protein, which is a key factor modulating actin polymerization in migrating cells. This mobility retardation disappeared after in vitro phosphatase treatment. Co-immunoprecipitation assays revealed the interaction of vinexin beta with WAVE2 as well as WAVE1 and N-WASP. Vinexin beta interacts with the proline-rich region of WAVE2 through the first and second SH3 domains of vinexin beta. Mutations disrupting the interaction impaired the ability of vinexin beta to increase the amount of WAVE2 protein. Treatments with proteasome inhibitors increased the amount of WAVE2, but did not have an additive effect with vinexin beta. Inhibition of protein kinase A (PKA) activity suppressed the vinexin-induced increase in WAVE2 protein, while activation of PKA increased WAVE2 expression without vinexin beta. These results suggest that vinexin beta regulates the proteasome-dependent degradation of WAVE2 in a PKA-dependent manner.
Mitsushima
Masaru
M
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Sezaki
Takuhito
T
Akahane
Rie
R
Ueda
Kazumitsu
K
Suetsugu
Shiro
S
Takenawa
Tadaomi
T
Kioka
Noriyuki
N
D000199:Actins / Q000378:metabolism; D000818:Animals; D002465:Cell Movement; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D022001:Focal Adhesions / Q000378:metabolism*; D047468:Immunoprecipitation; D051379:Mice; D009124:Muscle Proteins / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D041681:NIH 3T3 Cells; D010749:Phosphoprotein Phosphatases / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D061988:Proteasome Inhibitors; D011485:Protein Binding; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism*; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000378:metabolism; D018909:src Homology Domains; D048868:Adaptor Proteins, Signal Transducing
D000199:Actins; D017868:Cyclic AMP-Dependent Protein Kinases; D009124:Muscle Proteins; D010749:Phosphoprotein Phosphatases; D011480:Protease Inhibitors; D061988:Proteasome Inhibitors; D051300:Wiskott-Aldrich Syndrome Protein Family; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C117452:Sorbs3 protein, mouse; D048868:Adaptor Proteins, Signal Transducing; C492303:Wasf2 protein, mouse; C495772:Wasl protein, mouse