Chromogranin B: isolation from pheochromocytoma, N-terminal sequence, tissue distribution and secretory vesicle processing.
The chromogranins/secretogranins are a family of neuroendocrine vesicle secretory proteins. Immunohistology and immunoblotting have suggested that a major soluble protein in human chromaffin granules may be chromogranin B (CgB). We purified from pheochromocytoma chromaffin granules an SDS-PAGE 110-120 kDa protein whose N-terminal sequence matched that previously deduced from a human CgB cDNA. An antibody directed against a synthetic human CgB N-terminal region specifically recognized the CgB N-terminus, though not the chromogranin A (CgA) N-terminus or the CgB C-terminus on immunoblots. An antiserum directed against CgB's C-terminus also visualized CgB but not CgA. By immunoblotting, CgB was a quantitatively major protein in human pheochromocytoma chromaffin granules, but a relatively minor in normal bovine adrenal medullary chromaffin granules. In a variety of normal bovine neuroendocrine tissues, the relative abundance of CgB immunoreactivity on immunoblots was: adrenal medulla greater than anterior pituitary greater than pancreas greater than small intestine, hypothalamus. Immunoblotting of neuroendocrine tissues (or their hormone storage vesicle cores) with both anti N-terminal and anti C-terminal CgB antisera suggested bidirectional cleavage or processing of CgB; in the anterior pituitary, a unique 40 kDa C-terminal fragment was observed. Bidirectional CgB cleavage was also suggested on immunoblots of chromaffin tissue from three species (human, bovine, rat). C-terminal processing of CgB was also confirmed by amino acid sequencing of SDS-PAGE-separated, polyvinylidene difluoride membrane-immobilized CgB fragments from pheochromocytoma chromaffin granules. Whether such fragments possess biological activity remains to be investigated.
Gill
B M
BM
Department of Medicine, University of California, San Diego.
Barbosa
J A
JA
Dinh
T Q
TQ
Garrod
S
S
O'Connor
D T
DT
D000310:Adrenal Gland Neoplasms / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002837:Chromaffin Granules / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D053378:Chromogranin B; D002864:Chromogranins / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007106:Immune Sera / Q000378:metabolism; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009490:Neurosecretory Systems / Q000378:metabolism; D010673:Pheochromocytoma / Q000737:chemistry* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D051381:Rats; D013045:Species Specificity; D014018:Tissue Distribution
C506134:CHGB protein, human; D053378:Chromogranin B; D002864:Chromogranins; D007106:Immune Sera; C506140:chromogranin B, rat