Recovery of responsiveness to ACTH and cAMP in a protein kinase-defective adrenal cell mutant following transfection with a protein kinase gene.
The cause and effect relationship between mutations in cAMP-dependent protein kinase activity and resistance of adrenocortical tumor cells to ACTH and cAMP was evaluated by transfection with cloned cDNAs encoding subunits of the mouse cAMP-dependent protein kinase. Protein kinase defective, Kin 8 adrenocortical tumor cells were transfected with pRev [an expression vector encoding the regulatory subunit of the type 1 cAMP-dependent protein kinase (RI)] or with pC alpha ev [an expression vector encoding the catalytic subunit of cAMP-dependent protein kinase (C)]. The pC alpha ev transformant recovered cAMP responsive protein kinase activity, whereas the pRev transformant recovered cAMP-binding activity, but did not recover cAMP responsive protein kinase activity. The pC alpha ev transformant concomitantly recovered steroidogenic and morphologic responsiveness to ACTH- and 8-bromo-cAMP, whereas the pRev transformant remained resistant to these effects of the hormone and cyclic nucleotide. Since Kin 8 cells recovered their responsiveness to ACTH and 8-bromo-cAMP following transfection with pC alpha ev we suggest that the defect in cAMP-dependent protein kinase activity is directly responsible for the ACTH- and cAMP-resistant phenotype of the Kin 8 mutant.
Wong
M
M
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
Schimmer
B P
BP
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000306:Adrenal Cortex Neoplasms; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D005796:Genes; D005822:Genetic Vectors; D007700:Kinetics; D009154:Mutation; D010957:Plasmids; D011494:Protein Kinases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D013256:Steroids / Q000096:biosynthesis; D013431:Sulfates / Q000494:pharmacology; D014162:Transfection; D015032:Zinc / Q000494:pharmacology; D019287:Zinc Sulfate
D013256:Steroids; D013431:Sulfates; D015124:8-Bromo Cyclic Adenosine Monophosphate; D019287:Zinc Sulfate; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D011494:Protein Kinases; D015032:Zinc