Affixin activates Rac1 via betaPIX in C2C12 myoblast.
Affixin/beta-parvin is an integrin-linked kinase (ILK)-binding focal adhesion protein highly expressed in skeletal muscle and heart. To elucidate the possible role of affixin in skeletal muscle, we established stable C2C12 cell line expressing T7-tagged human affixin (C2C12-affixin cells). Exogenous expression of affixin promotes lamellipodium formation where affixin, ILK alphap21-activated kinase (PAK)-interactive exchange factor (PIX) and betaPIX accumulate. The association of affixin and betaPIX was confirmed by immunoprecipitation and pull down assay. In C2C12-affixin cells, an increased level of activated Rac1 but not Cdc42 was observed, and mutant betaPIX lacking guanine nucleotide exchange factor activity inhibited lamellipodium formation. These results suggest that affixin is involved in reorganization of subsarcolemmal cytoskeletal actin by activation of Rac1 through alpha and betaPIXs in skeletal muscle.
Matsuda
Chie
C
Neuroscience Research Institute, AIST, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan. c-matsuda@aist.go.jp
Kameyama
Kimihiko
K
Suzuki
Atsushi
A
Mishima
Wataru
W
Yamaji
Satoshi
S
Okamoto
Harumasa
H
Nishino
Ichizo
I
Hayashi
Yukiko K
YK
D000185:Actinin / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D064067:Rho Guanine Nucleotide Exchange Factors; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; C486591:PARVB protein, human; C107953:RAC1 protein, human; D064067:Rho Guanine Nucleotide Exchange Factors; D000185:Actinin; D020830:rac1 GTP-Binding Protein