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Acylation of Gα 13 is important for its interaction with thrombin receptor, transforming activity and actin stress fiber formation
Author(s) -
Ponimaskin Evgeni,
Behn Holger,
Adarichev Vyacheslav,
Voyno-Yasenetskaya Tatyana A.,
Offermanns Stefan,
Schmidt Michael F.G.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01845-7
Subject(s) - palmitoylation , heterotrimeric g protein , mutant , g protein coupled receptor , stress fiber , cysteine , serine , biochemistry , chemistry , receptor , g protein , microbiology and biotechnology , biology , cytoskeleton , cell , phosphorylation , gene , enzyme
Palmitoylation of α‐subunits in heterotrimeric G proteins has become a research object of growing attention. Following our recent report on the acylation of the mono‐palmitoylated Gα 12 [Ponimaskin et al., FEBS Lett. 429 (1998) 370–374], we report here on the identification of three palmitoylation sites in the second member of the G 12 family, Gα 13 , and on the biological significance of fatty acids on the particular sites. Using mutants of α 13 in which the potentially palmitoylated cysteine residues (Cys) were replaced by serine residues, we find that Cys‐14, Cys‐18 and Cys‐37 all serve as palmitoylation sites, and that the mutants lacking fatty acids are functionally defective. The following biological functions of Gα 13 were found to be inhibited: coupling to the PAR1 thrombin receptor, cell transformation and actin stress fiber formation. Results from established assays for the above functions with a series of mutants, including derivatives of the constitutively active mutant Gα 13 Q226L, revealed a graded inhibitory response on the above mentioned parameters. As a rule, it appears that palmitoylation of the N‐proximal sites (e.g. Cys‐14 and Cys‐18) contributes more effectively to biological function than of the acylation site located more internally (Cys‐37). However, the mutant with Cys‐37 replaced by serine is more severely inhibited in stress fiber formation (80%) than in cell transformation (50%), pointing to the possibility of a differential involvement of the three palmitoylation sites in Gα 13 .