Premium
Regulation of hematopoietic‐specific G‐protein Gα 15 and Gα 16 by protein kinase C
Author(s) -
Gu Jennifer L.,
Lu Wei,
Xia Chunzhi,
Wu Xiushan,
Liu Mingyao
Publication year - 2003
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10455
Subject(s) - heterotrimeric g protein , phosphorylation , protein kinase c , biology , microbiology and biotechnology , g protein , protein kinase a , g alpha subunit , protein subunit , signal transduction , biochemistry , gene
Heterotrimeric G proteins mediate cell growth and differentiation by coupling cell surface receptors to intracellular effector enzymes. The G‐protein α subunit, Gα 16 , and its murine homologue Gα 15 , are expressed specifically in hematopoietic cells and their expression is highly regulated during differentiation of normal and leukemic cells. In this study, we examined the phosphorylation of Gα 15 /Gα 16 and its role in receptor and effector coupling. We observed a PMA‐stimulated intact cell phosphorylation of Gα 15 in COS7 cells transfected with Gα 15 and protein kinase Cα (PKCα), and phosphorylation of endogenous Gα 16 in HL60 cells. We also showed that peptides derived from the two G‐proteins were phosphorylated in vitro using purified brain PKC. Furthermore, we identified the putative phosphorylation site and showed that mutation or deletion of this PKC phosphorylation site inhibited phospholipase C (PLC) activation. The behavior of double mutants with the constitutively active G‐protein mutation (QL‐mutant) and mutation in the putative phosphorylation site suggests that the phosphorylation site of Gα 15/16 is essential for receptor‐coupled activation of PLC, but not for direct interaction of the G‐protein with PLC‐β. J. Cell. Biochem. 88: 1101–1111, 2003. © 2003 Wiley‐Liss, Inc.