ISSN:
0730-2312
Keywords:
Gα2
;
phosphorylation
;
S113A
;
Dictyostelium discoideum
;
cAMP
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
The Gα2-subunit of Dictyostelium discoideum is essential to the initial stage of the cell's developmental life cycle. In response to the extracellular chemoattractant, cAMP, Gα2 is activated and transiently phosphorylated on serine-113 [Chen et al. (1994): J Biol Chem 269:20925-20930]. The role of Gα2 phosphorylation remains elusive; cells expressing the S113A, nonphosphorylated mutation of Gα2 appear to proceed through the developmental phase normally. To gain insight into the function of Gα2 phosphorylation, the conditions for Gα2 phosphorylation were examined using a variety of α-subunit point mutations and chimeras. Mutations that block the G protein activation cycle prior to or at the hydrolysis of GTP (Gα2-S45A, Gα2-G207A, and Gα2-Q208L) preclude Gα2 phosphorylation in vivo. Phosphorylation of the Gα2-Q208L mutation does however occur in an in vitro phosphorylation assay. It appears that Gα2 phosphorylation, shown previously in vivo to require the cAMP receptor, also requires signaling through the G2 pathway. Results from the in vitro assay suggest that the substrate for phosphorylation is the α-subunit monomer. J. Cell. Biochem. 66:268-276, 1997. © 1997 Wiley-Liss, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
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