| First Author | Beebe SJ | Year | 1990 |
| Journal | Mol Endocrinol | Volume | 4 |
| Issue | 3 | Pages | 465-75 |
| PubMed ID | 2342480 | Mgi Jnum | J:35065 |
| Mgi Id | MGI:82519 | Doi | 10.1210/mend-4-3-465 |
| Citation | Beebe SJ, et al. (1990) Molecular cloning of a tissue-specific protein kinase (C gamma) from human testis--representing a third isoform for the catalytic subunit of cAMP-dependent protein kinase. Mol Endocrinol 4(3):465-75 |
| abstractText | Two different mammalian genes for the catalytic subunit (C) of cAMP-dependent protein kinase have previously been characterized (C alpha, C beta). In the present study, we report the molecular cloning of a third isoform of C, from a human testis cDNA library, as well as the isolation of human cDNAs for C alpha and C beta. This third form of C, which we will designate C gamma, is clearly derived from a distinct gene and shows a tissue-specific expression. A close evolutionary relation between C gamma and C alpha was suggested by nucleotide homologies (86% inside the open reading frame, 81% in the 3'-untranslated region). Thus, the C gamma cDNA cross-hybridized with the 2.8 kilobase (kb) C alpha mRNA, present at high levels in most human tissues, as well as with a 1.8 kb C gamma-specific mRNA, which was only found at detectable levels in human testis. However, at the amino acid level, C alpha and C beta showed a close relationship (93% homology), whereas C gamma diverged significantly from both C alpha (83%) and C beta (79%). Taken together with the tissue-specific expression of C gamma, this suggests a pressure on C gamma during evolution, acting to modulate it in a functionally specific way. Certain amino acid substitutions make C gamma a distinct member of the cAMP-dependent subfamily of protein kinases, and suggest that C gamma may be distinct in its protein substrate specificity or its interaction with the different regulatory subunits. |
