Direct activation of fission yeast adenylate cyclase by the Gpa2 Galpha of the glucose signaling pathway.
G protein-mediated signaling is implicated in yeast and fungal cAMP pathways. By two-hybrid screens and pull-down experiments, we show that the fission yeast Gpa2 Galpha binds an N-terminal domain of adenylate cyclase, comprising a moderately conserved sequence within a region otherwise poorly related to other fungal adenylate cyclases. Overexpressing this domain in yeast perturbs cAMP signaling, which is restored by Gpa2 coexpression. Mutations affecting this domain, over 1,100 residues from the catalytic domain, alter glucose-triggered cAMP signaling. This is evidence for direct activation of adenylate cyclase by a fungal G protein and suggests a distinct activation mechanism from that of mammals.
Ivey
F Douglas
FD
Biology Department, Boston College, 140 Commonwealth Avenue, Higgins Hall, Room 401B, Chestnut Hill, MA 02467, USA.
Hoffman
Charles S
CS
D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism*; D019943:Amino Acid Substitution; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004789:Enzyme Activation; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D005947:Glucose / Q000502:physiology*; D007700:Kinetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016297:Mutagenesis, Site-Directed; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D017931:DNA Primers; D044385:GTP-Binding Protein alpha Subunits; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C083907:Gpa2 protein, S cerevisiae; C540695:gpa2 protein, S pombe; D000262:Adenylyl Cyclases; D005947:Glucose