Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The putative guanine nucleotide binding (G)-protein involved in transduction of signals from the TCR/CD3 complex has not been identified. We have used a UV-photoaffinity labeling technique to covalently attach [alpha-32P]GTP to human lymphocyte and thymocyte membrane proteins. Ten bands specifically labeled with [32P]GTP were detected by SDS-PAGE and autoradiography in T lymphocyte membranes. Among these, a 40-kDa protein was identified by immunoblotting as the alpha-subunit of the adenylate cyclase-inhibiting G-protein, Gi, and two proteins of 44 and 46 kDa were identified as the alpha-subunits of adenylate cyclase stimulating G-protein (Gs). These proteins also served as substrates for ADP-ribosylation by pertussis toxin and cholera toxin, respectively. Comparison of GTP-labeled membrane proteins from immature and more mature thymocytes and blood T lymphocytes, revealed that bands of 26, 30, 34, 40, 44 and 46 kDa were absent or weakly labeled in immature thymocytes, intermediate in mature thymocytes, and strongest in blood T cells. Similar increases were seen in ADP ribosylation of the substrates for pertussis, cholera, and botulinum C3 toxin. However, corresponding quantitative changes in Gi and Gs were not detected by immunoblotting, which suggests that the increased labeling is caused by enhanced affinity of the proteins for GTP rather than by increased amount of protein during thymic maturation. A concomitant maturation of GTP-induced cAMP production was seen in the cell populations, but no such change occurred in direct activation of adenylate cyclase by forskolin. The changes in some (but not all) GTP-binding proteins during acquisition of immunocompetence indicates their importance in T lymphocyte physiology.
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PMID:Functional maturation of human T lymphocytes is accompanied by changes in the G-protein pattern. 215 32

The primary structure of the alpha-subunit of the adenylate cyclase-inhibiting G-protein (Gi) has been deduced from the nucleotide sequence of cloned DNA complementary to the bovine cerebral mRNA encoding the polypeptide. A much higher degree of amino acid sequence homology is observed between the alpha-subunits of Gi and transducin (68%) than between those of Gi and the adenylate cyclase-stimulating G-protein (Gs) (43%) or between those of transducin and Gs (42%).
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PMID:Primary structure of the alpha-subunit of bovine adenylate cyclase-inhibiting G-protein deduced from the cDNA sequence. 241 65