RRC ID 31015
Author Gundersen RE.
Title Phosphorylation of the G protein alpha-subunit, G alpha 2, of Dictyostelium discoideum requires a functional and activated G alpha 2.
Journal J Cell Biochem
Abstract The G alpha 2-subunit of Dictyostelium discoideum is essential to the initial stage of the cell's developmental life cycle. In response to the extracellular chemoattractant, cAMP, G alpha 2 is activated and transiently phosphorylated on serine-113 [Chen et al. (1994): J Biol Chem 269:20925-20930]. The role of G alpha 2 phosphorylation remains elusive; cells expressing the S113A, nonphosphorylated mutation of G alpha 2 appear to proceed through the developmental phase normally. To gain insight into the function of G alpha 2 phosphorylation, the conditions for G alpha 2 phosphorylation were examined using a variety of alpha-subunit point mutations and chimeras. Mutations that block the G protein activation cycle prior to or at the hydrolysis of GTP (G alpha 2-S45A, G alpha 2-G207A, and G alpha 2-Q208L) preclude G alpha 2 phosphorylation in vivo. Phosphorylation of the G alpha 2-Q208L mutation does however occur in an in vitro phosphorylation assay. It appears that G alpha 2 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 alpha-subunit monomer.
Volume 66(2)
Pages 268-76
Published 1997-8-1
PII 10.1002/(SICI)1097-4644(19970801)66:2<268::AID-JCB13>3.0.CO;2-D
PMID 9213227
MeSH Animals Dictyostelium / genetics Dictyostelium / metabolism* Dictyostelium / physiology GTP-Binding Proteins / genetics GTP-Binding Proteins / metabolism* GTP-Binding Proteins / physiology* Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology Mutagenesis, Site-Directed Phenotype Phosphorylation / drug effects Receptors, Cyclic AMP / drug effects Receptors, Cyclic AMP / metabolism Recombinant Fusion Proteins / metabolism
IF 4.237
Times Cited 5
Cellular slime molds S90405