Distribution and properties of type I and type II binding proteins in the cyclic adenosine 3':5'-monophosphate-dependent protein kinase system in Wilms' tumor.
We compared the relative amounts and properties of cyclic adenosine 3':5'-monophosphate (cAMP)-binding proteins in surgical specimens of Wilms' tumor and normal kidney. Cytosolic fractions of both tissues contained type I and type II isozymes of cAMP-dependent protein kinase (adenosine triphosphate: protein phosphotransferase, EC 2.7.1.37). Among tumor samples, the mean ratio of type I to type II cAMP-binding activity was 2.76 +/- 0.52 (S.D.) contrasted with 1.36 +/- 0.23 for normal kidney (p less than 0.001). The total soluble cAMP-binding activities in normal and malignant tissues differed only slightly. Photoaffinity labeling of cytosol from either tissue, using cyclic adenosine 3':5'-[8-azido-32P]monophosphate, disclosed three cAMP-binding proteins (Mr 47,000, 51,000, and 55,000) that were identified as regulatory subunits of the holoenzyme. Three lower-molecular-weight proteins with unknown function were considered to be proteolytic products of the larger proteins. The Mr 47,000 protein, a monomeric regulatory subunit of type I kinase, was clearly the dominant protein in tumor specimens, but it was much less abundant in normal kidney. The temperature sensitivities of the cAMP-binding proteins and their dissociation constants for cyclic adenosine 3':5'-[8-azido-32P]monophosphate incorporation did not differ appreciably between tumor and normal tissues. Wilms' tumor appears to have a full complement of regulatory subunits of cAMP-dependent protein kinase that are capable of normal cellular function.
D006528:Carcinoma, Hepatocellular / Q000201:enzymology; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007668:Kidney / Q000201:enzymology*; D007680:Kidney Neoplasms / Q000201:enzymology*; D008099:Liver / Q000201:enzymology; D008113:Liver Neoplasms / Q000201:enzymology; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000302:isolation & purification*; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification* / Q000378:metabolism; D012016:Reference Values; D009396:Wilms Tumor / Q000201:enzymology*
D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D007527:Isoenzymes; D009363:Neoplasm Proteins; D011494:Protein Kinases