Phosphorylation and O-Glycosylation Sites of Human Chromogranin A (CGA79-439) from Urine of Patients with Carcinoid Tumors (original) (raw)
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PROTEOMICS, 2004
Bovine chromoganin B (CGB)/secretogranin I, an acidic protein with a sequence of 626 residues and an isoelectric point of 5.2 is a major member of the chromogranin/secretogranin (CG/Sg) family. The difference between the theoretical molecular mass (76 kDa) and the value estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis results from posttranslational modifications (glycosylation, phosphorylation and sulfation) and from the abundance of acidic residues (D 4.6%, and E 16.5%). Although the sequence of CGB is known, the structural analyses of the post-translational modifications have so far not been carried out. In the present study, using a combination of proteomic techniques including two-dimensional gel electrophoresis, Western blot, high-performance liquid chromatography purification, enzymatic digestion, sequencing, carbohydrate analysis, matrix-assisted laser desorption/ ionization-time of flight and liquid chromatography mass spectrometry analysis, we have located 18 post-translational modifications on bovine CGB, isolated from adrenal medulla chromaffin granules. Furthermore, we have identified at the molecular level the presence of a mutation M/V on position 577 of natural CGB. All together these data reflect the complex structure of this protein marker of the neuroendocrine system.
Rapid, high-yield isolation of human chromogranin A from chromaffin granules of pheochromocytomas
Neuropeptides, 1992
Chromogranin A (CgA) is a useful probe of human neuroendocrine neoplasia and exocytotic sympathoadrenal activity, but the application of CgA immunoassays has not been widespread because of limited availability of purified human CgA. Here we describe a rapid, high yield isolation of human CgA. After obtaining and lysing pheochromocytoma chromaffin granules, the soluble core proteins (chromogranins) were depleted of dopamine-betahydroxylase by passage over a concanavalin A-Sepharose affinity column, then lyophilized, resuspended in volatile buffer, and gel filtered on Sephacryl S-300. SDS-PAGE-analyzed column fractions contained homogeneous human CgA, which was verified structurally (N-terminal amino acid sequence) and immunologically (radioimmunoassay and immunoblot). The overall 22.6 mg yield of purified CgA represented 5.7% of the starting vesicle core protein. This preparation will be useful in evaluating the sympathoadrenal system and endocrine neoplasia in man.
Endocrine Pathology, 2003
Chromogranins are the major components of the secretory granules of most neuroendocrine cells. Within the secretory pathway, chromogranins are involved in granulogenesis, and in sorting and processing of secretory protein cargo prior to secretion. Once secreted, they have hormonal, autocrine, and paracrine activities. The chromogranin family includes chromogranins A (CgA) and B (CgB) and secretogranin II (SgII, once called chromogranin C). The related "granins" NESP55, 7B2, secretogranin III/1B 1075 (SgIII), and secretogranin IV/HISL-19 antigen (SgIV), are also sometimes included when considering the chromogranins. While it is useful to consider the granin proteins as a family with many common features, it is also necessary to examine the distinct features and properties of individual members of the granin family to understand fully their functions, employ them efficiently as tissue, serum, and urinary markers for neuroendocrine neoplasia, and develop an evolutionary-biologic perspective on their contribution to mammalian physiology. Recent advances in chromogranin research include establishing the role of CgA in granulogenesis and the role of CgB in nuclear transcription; new biologic activities for CgA-, CgB-, and SgII-derived peptides; and new marker functions for granins and their proteolytically processed products in endocrine neoplasias.
Primary structure of rat chromogranin A and distribution of its mRNA
FEBS Letters, 1988
The primary structure of rat chromogranin A has been deduced from a rat adrenal cDNA clone. A comparison of rat and bovine chromogranin A reveals several similar features: clusters of polyglutamic acid, similar amino acid composition, position of seven of 10 pairs of basic ammo acids, identical placement of the only two cysteine residues, a highly conserved N-and C-terminus, and a sequence homologous to porcine pancreastatin 149 [(1986) Nature 324, 4764781. Unique features of rat chromogranin A are an eicosaglutamine sequence and two potential N-linked glycosylation sites. Chromogranin A mRNA is detectable in adrenal medulla, anterior pituitary, cerebral cortex, and hippocampus, as well as tumor cell lines derived from pancreas, pituitary, and adrenal medulla. cDNA cloning; Sequence homology; mRNA; Chromogranin A;
Journal of Endocrinology, 2000
Chromogranin A (CgA) and chromogranin B (CgB) are acidic proteins stored in and released from hormone granules in endocrine and neuroendocrine tissue. The chromogranins are postulated to serve as pro-hormones to generate biologically active peptides, which may influence hormonal release and vascular functions or have antibacterial functions. Although N-terminal and C-terminal regions show some species amino acid homology, the chromogranins as a whole display considerable interspecies differences, which prevents their use in comparative studies of biological functions. We present four new radioimmunoassays for the measurement of defined N-terminal regions of CgA and CgB. A new radioimmunoassay for measurement of intact bovine CgA has also been developed. With these assays and two previously published ones, we have compared the cross-reactivity of chromogranins from man, cattle, sheep, goat, pig and horse and compared adrenomedullar content and serum levels of CgA from these species. ...