Elevation of intracellular cAMP levels by dominant active heterotrimeric G protein alpha subunits ScGP-A and ScGP-C in homobasidiomycete, Schizophyllum commune.
In many fungi, the heterotrimeric G protein alpha subunits, and/or small G protein (RAS) control intracellular cAMP levels. But it is not clear which types of G proteins modulate cAMP levels in homobasidiomycete (mushrooms). To explain the mechanism, we expressed dominant active RAS (a homolog of S. cerevisiae RAS1) in homobasidiomycete Schizophyllum commune and compared the cAMP levels in the transformed clones with those of clones expressing dominant active heterotrimeric G protein alpha subunits ScGP-A, B, and C. The results demonstrated that the dominant active ScGP-A and C elevated the intracellular cAMP levels. In contrast, the dominant active S. commune RAS gene did not affect the cAMP levels, even though colony growth and formation of fruiting bodies were apparently repressed. These data suggest that the heterotrimeric G protein alpha subunits are involved in the mechanism of cAMP regulation, and that RAS modulates another signal-transduction pathway regulating cell growth and differentiation.
Yamagishi
Kenji
K
National Agricultural Research Center for the Tohoku Region, National Agricultural Research Organization, Fukushima, Japan. yamagisi@affrc.go.jp
Kimura
Toshiyuki
T
Suzuki
Masahiro
M
Shinmoto
Hiroshi
H
Yamaki
Ko-Ji
KJ
D019943:Amino Acid Substitution; D001483:Base Sequence; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism*; D048690:Fruiting Bodies, Fungal / Q000378:metabolism / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D015870:Gene Expression; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D025282:Mycelium / Q000378:metabolism / Q000502:physiology; D010957:Plasmids; D017354:Point Mutation; D012567:Schizophyllum / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology
D005656:Fungal Proteins; D044385:GTP-Binding Protein alpha Subunits; D000242:Cyclic AMP; D018631:ras Proteins