Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The treatment of primary cultures of bovine adrenocortical cells with nanomolar concentrations of ACTH induces a 10-fold increase in the synthesis of a secreted protein of apparent molecular mass 195 kDa on reducing SDS-polyacrylamide gels. This corticotropin-induced secreted protein (CISP) appears to be an oligomeric calcium-binding protein. Its secretion under serum-free culture conditions is sustained over 4 days in the continuous presence of ACTH. Induction of CISP secretion by ACTH is mimicked by cAMP analogs and adenylate cyclase activators. We report here the purification of CISP to apparent homogeneity with an overall yield of 43% using a combination of heparin-agarose and Mono-Q chromatographies. The NH2-terminal amino acid sequence and the sequence of several tryptic peptides revealed that CISP is structurally related to the members of the thrombospondin (TSP) family. Among these members, bovine CISP appeared to be more homologous to mouse TSP2 (85% identity in the 29 amino acid long NH2-terminal sequence) than to TSP1 (18% identity in the same region). We also observed that CISP binds Ca2+ and is an adhesive protein for bovine adrenocortical cells. Thus, CISP possesses both structural and functional properties of thrombospondins. Whether CISP represents the bovine form of TSP2 or a novel member of the expanding thrombospondin family will need to be elucidated by cloning and sequencing of a larger portion of the molecule.
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PMID:Corticotropin-induced secreted protein, an ACTH-induced protein secreted by adrenocortical cells, is structurally related to thrombospondins. 838 99

CISP (corticotropin-induced secreted protein) is a secreted protein recently purified in our laboratory from the conditioned medium of ACTH-treated bovine adrenocortical cells. Partial amino acid sequencing of CISP revealed homology with thrombospondins (TSPs), a family of adhesive proteins and in particular with TSP2. We report here the characterization of the molecular structure of CISP. Analysis of CISP by polyacrylamide gel electrophoresis in the absence or presence of SDS indicated an apparent molecular mass approximately equal to 600 kDa for the unreduced protein and an apparent molecular mass of 195 kDa after reduction by 2-mercaptoethanol. The sedimentation coefficient of CISP determined by ultracentrifugation on sucrose gradients was shifted from 9.7 S in the absence to 5.7 S in the presence of 2-mercaptoethanol. These data are consistent with a trimeric organization of the CISP molecule in which 195-kDa monomers would be linked together by disulfide bonds. The trimeric structure of CISP could be observed by rotary shadowing/electron microscopy, where CISP appeared to be composed of three equally electron-dense nodules and of a fourth nodule formed by the close association of three smaller fragments. The overall size of the molecule was 60 nm. We also observed that CISP is sulfated and glycosylated. Using glycosylation inhibitors, we could determine that CISP is synthesized as a 175-kDa core protein, is then matured into a 190-kDa high-mannose form and secreted as a 195-kDa mature protein. Inhibition of sulfation by chlorate did not prevent CISP secretion, whereas inhibition of glycosylation by tunicamycin blocked it. Taken together, these data indicate that the TSP2-related CISP molecule presents both structural and functional properties very similar to those of TSP1. CISP differs greatly, however, from TSP1 by the inducibility of its synthesis by cAMP.
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PMID:The molecular structure of corticotropin-induced secreted protein, a novel member of the thrombospondin family. 839 19