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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1993-6-29
pubmed:abstractText
A series of mutant cell lines (Kin) were previously isolated from Y1 adrenocortical tumor cells based on their ability to resist the growth-inhibitory effects of 8-bromo cAMP. In these Kin clones, cAMP-dependent protein kinase (cAMPdPK) was resistant to activation by cAMP as the consequence of mutations affecting the type I regulatory subunit (RI) of the enzyme. This study shows that the cAMP-resistant phenotypes of mutant clones Kin-2, Kin-7, and Kin-8 were associated with single base changes causing substitutions, respectively, of Glu for Gly200, Trp for Arg334, and Asp for Gly324 in the RI protein. By expressing the mutant Trp334 and Asp324 forms of RI under the control of an inducible promoter in Y1 cells, the causal relationship between these RI mutations and impairment of cAMP-stimulated adrenocortical responses was studied. Expression of the mutant RI forms rendered cAMPdPK resistant to activation by cAMP and decreased cAMP-stimulated cell rounding, steroid production, and growth inhibition. These observations indicate that the cAMP-resistant phenotype of Kin mutant clones resulted specifically from single mutational events in RI and thus establish the importance of cAMPdPK as an essential regulator of adrenocortical function. Unlike the original Kin mutant clones, transformants expressing the mutant forms of RI had adenylyl cyclases that were resistant to activation by ACTH, forskolin, or sodium fluoride. These results indicate that there may be a hitherto unappreciated mechanism of regulation of adenylyl cyclase activity by cAMPdPK.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
477-87
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:8388994-8-Bromo Cyclic Adenosine Monophosphate, pubmed-meshheading:8388994-Adenylate Cyclase, pubmed-meshheading:8388994-Adrenal Cortex Neoplasms, pubmed-meshheading:8388994-Animals, pubmed-meshheading:8388994-Base Sequence, pubmed-meshheading:8388994-Blotting, Northern, pubmed-meshheading:8388994-Cell Division, pubmed-meshheading:8388994-Cyclic AMP, pubmed-meshheading:8388994-DNA, pubmed-meshheading:8388994-Humans, pubmed-meshheading:8388994-Mice, pubmed-meshheading:8388994-Molecular Sequence Data, pubmed-meshheading:8388994-Mutation, pubmed-meshheading:8388994-Polymerase Chain Reaction, pubmed-meshheading:8388994-Protein Kinases, pubmed-meshheading:8388994-Sulfates, pubmed-meshheading:8388994-Tumor Cells, Cultured, pubmed-meshheading:8388994-Zinc, pubmed-meshheading:8388994-Zinc Sulfate
pubmed:year
1993
pubmed:articleTitle
Molecular basis for the 3',5'-cyclic adenosine monophosphate resistance of Kin mutant Y1 adrenocortical tumor cells.
pubmed:affiliation
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't