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Activity of β3‐β4 loop of the PH domain is required for the membrane targeting of SWAP‐70
Author(s) -
Fukui Yasuhisa,
Wakamatsu Isamu,
Tachikawa Hiroyuki,
Okamura Yoshihiko,
Tanaka Takayuki,
Ihara Sayoko
Publication year - 2007
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216540701222880
Subject(s) - phosphatidylinositol , pleckstrin homology domain , mutant , membrane ruffling , microbiology and biotechnology , chromosomal translocation , phosphatidylinositol 4,5 bisphosphate , green fluorescent protein , chemistry , protein kinase domain , biophysics , swap (finance) , membrane , kinase , biochemistry , biology , gene , cytoskeleton , finance , cell , economics
SWAP‐70 translocates to the plasma membrane in a phosphoinositide 3‐kinase (PI 3‐kinase)‐dependent manner and contributes to membrane ruffling. It binds to phosphatidylinositol trisphosphate (PtdIns(3,4,5)P3) through its PH domain, which is essential for the membrane translocation after EGF stimulation. We examined the behavior of the SWAP‐70s which have mutations in the β3/β4 loop of the PH domain. The two mutants fused to green fluorescent protein (GFP) carrying the mutations failed to translocate to the plasma membrane. The sole PH domains carrying the same mutations behaved similarly. The PtdIns(3,4,5)P3 binding activity of two mutants was comparable to that of the wild‐type protein. These results suggest that translocation of SWAP‐70 largely depends on the activity of the PH domain, and that not only PtdIns(3,4,5)P3 binding activity, but also some additional activity of the PH domain is required for the translocation.IUBMB Life, 59: 99‐103, 2007