Regulation and function of G alpha protein subunits in Dictyostelium.
We have examined the developmental regulation and function of two G alpha protein subunits, G alpha 1 and G alpha 2, from Dictyostelium. G alpha 1 is expressed in vegetative cells through aggregate stages while G alpha 2 is inducible by cAMP pulses and preferentially expressed in aggregation. Our results suggest that G alpha 2 encodes the G alpha protein subunit associated with the cAMP receptor and mediates all known receptor-activated intracellular signal transduction processes, including chemotaxis and gene regulation. G alpha 1 appears to function in both the cell cycle and development. Overexpression of G alpha 1 results in large, multinucleated cells that develop abnormally. The central role that these G alpha proteins play in signal transduction processes and in controlling Dictyostelium development is discussed.
Kumagai
A
A
Department of Biology, University of California, San Diego, La Jolla 92093.
Pupillo
M
M
Gundersen
R
R
Miake-Lye
R
R
Devreotes
P N
PN
Firtel
R A
RA
D002872:Chromosome Deletion; D000242:Cyclic AMP / Q000494:pharmacology; D004023:Dictyostelium / Q000254:growth & development* / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D009154:Mutation; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D012331:RNA, Fungal; D012333:RNA, Messenger; D000242:Cyclic AMP; D019204:GTP-Binding Proteins