Abstract
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.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenylyl Cyclases / genetics
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Adenylyl Cyclases / metabolism*
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Amino Acid Substitution
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Base Sequence
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Cloning, Molecular
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DNA Primers
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Enzyme Activation
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GTP-Binding Protein alpha Subunits / genetics
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GTP-Binding Protein alpha Subunits / metabolism*
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Genotype
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Glucose / physiology*
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Kinetics
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Molecular Sequence Data
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Mutagenesis, Insertional
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Mutagenesis, Site-Directed
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Schizosaccharomyces / enzymology*
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Schizosaccharomyces / genetics
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Schizosaccharomyces pombe Proteins / metabolism
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Signal Transduction / physiology
Substances
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DNA Primers
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GTP-Binding Protein alpha Subunits
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Saccharomyces cerevisiae Proteins
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Schizosaccharomyces pombe Proteins
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Gpa2 protein, S cerevisiae
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gpa2 protein, S pombe
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Adenylyl Cyclases
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Glucose