Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-diabetic sulphonylureas act via high affinity binding sites coupled to K-ATP channels. Endosulfine, an endogenous ligand for these binding sites, was shown to exist in two molecular forms, alpha and beta, in both the pancreas and the central nervous system. We describe here the isolation, and partial structural characterization of alpha endosulfine derived from porcine brains by means of a series of chromatography runs and gel electrophoresis. Porcine alpha endosulfine is a protein with a molecular mass of 13,196 daltons as determined by mass spectrometry and which is N-terminally blocked. Tryptic digestion followed by separation of the fragments by HPLC and automated Edman degradation yielded a total of 72 amino acids in four partial sequences. Comparison of these sequences with that present in the National Biomedical Research Foundation protein data bank indicated a 82% identity with a 112-amino acid protein with a molecular mass of 12,353 daltons called "cyclic AMP-regulated phosphoprotein-19', isolated from the bovine brain as a substrate for protein kinase A.
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PMID:Endosulfine, endogenous ligand for the sulphonylurea receptor: isolation from porcine brain and partial structural determination of the alpha form. 863 64

ARPP-16 and ARPP-19 are closely related cAMP-regulated phosphoproteins that were initially discovered in mammalian brain as in vitro substrates for protein kinase A (PKA). ARPP-16 is enriched in dopamine-responsive medium spiny neurons in the striatum, while ARPP-19 is ubiquitously expressed. ARPP-19 is highly homologous to alpha-endosulfine and database searches allowed the identification of novel related proteins in D. melanogaster, C. elegans, S. mansoni and yeast genomes. Using isoform-specific antibodies, we now show that ARPP-19 is composed of at least two differentially expressed isoforms (termed ARPP-19 and ARPP-19e/endosulfine). All ARPP-16/19 family members contain a conserved consensus site for phosphorylation by PKA (RKPSLVA in mammalian ARPP-16 and ARPP-19), and this site was shown to be efficiently phosphorylated in vitro by PKA. An antibody that specifically recognized the phosphorylated form of ARPP-16/19/19e was used to examine the phosphorylation of ARPP-16/19 family members in intact cells. In striatal slices, the phosphorylation of ARPP-16 was increased in response to activation of D(1)-type dopamine receptors, and decreased in response to activation of D(2)-type dopamine receptors. In non-neuronal cells, ARPP-19 was highly phosphorylated in response to activation of PKA. These results establish that ARPP-16/19 proteins constitute a family of PKA-dependent intracellular messengers that function in all cells. The high levels of ARPP-16 in striatal neurons and its bi-directional regulation by dopamine suggest a specific role in dopamine-dependent signal transduction. The conservation of this protein family through evolution suggests that it subserves an important cellular function that is regulated by PKA.
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PMID:ARPP-16/ARPP-19: a highly conserved family of cAMP-regulated phosphoproteins. 1127 79