Identification of a human cDNA encoding a protein that is structurally and functionally related to the yeast adenylyl cyclase-associated CAP proteins.
The adenylyl cyclases of both Saccharomyces cerevisiae and Schizosaccharomyces pombe are associated with related proteins named CAP. In S. cerevisiae, CAP is required for cellular responses mediated by the RAS/cyclic AMP pathway. Both yeast CAPs appear to be bifunctional proteins: the N-terminal domains are required for the proper function of adenylyl cyclase, while loss of the C-terminal domains results in morphological and nutritional defects that appear to be unrelated to the cAMP pathways. Expression of either yeast CAP in the heterologous yeast suppresses phenotypes associated with loss of the C-terminal domain of the endogenous CAP but does not suppress loss of the N-terminal domain. On the basis of the homology between the two yeast CAP proteins, we have designed degenerate oligonucleotides that we used to detect, by the polymerase chain reaction method, a human cDNA fragment encoding a CAP-related peptide. Using the polymerase chain reaction fragment as a probe, we isolated a human cDNA clone encoding a 475-amino-acid protein that is homologous to the yeast CAP proteins. Expression of the human CAP protein in S. cerevisiae suppresses the phenotypes associated with loss of the C-terminal domain of CAP but does not suppress phenotypes associated with loss of the N-terminal domain. Thus, CAP proteins have been structurally and, to some extent, functionally conserved in evolution between yeasts and mammals.
Matviw
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Department of Medical Biochemistry, University of Calgary Health Science Centre, Alberta, Canada.
Yu
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Young
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D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D029721:Drosophila Proteins; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D048868:Adaptor Proteins, Signal Transducing; C489549:CAP1 protein, human; C410502:Capt protein, Drosophila; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D005656:Fungal Proteins; D008840:Microfilament Proteins; C073751:SRV2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA