TY - JOUR

T1 - Reserpine‐Induced Processing of Chromogranin A in Cultured Bovine Adrenal Chromaffin Cells

AU - Watkinson, Allan

AU - Robinson, Iain

PY - 1992/3/31

Y1 - 1992/3/31

N2 - Abstract: The effect of reserpine on the processing of the secretory granule protein chromogranin A (CgA) in isolated bovine adrenal chromaffin cells was investigated using two radioimmunoassays employing site‐specific antisera. The two antisera were directed against closely associated regions of the CgA molecule which would be exposed by specific processing: antiserum L331 was raised against the C‐terminus of the regulatory peptide pancreastatin, and the second anti‐serum, L300, was raised against the synthetic peptide [Tyr0]CgA306–313 (YLSKEWEDA), a sequence that lies immediately C‐terminal to pancreastatin and adjacent to a dibasic amino acid cleavage site. Chronic reserpine treatment of chromaffin cells produced a time‐ and dose‐dependent increase in processing, as demonstrated by an increase in pancreastatin‐ and YLSKEWEDA‐immunoreactivity (ir). The reserpine‐induced rise in pancreastatin‐ir was due predominantly to an increase in pancreastatin 1–47, whereas the rise in YLSKEWEDA‐ir was due to increases in three polypep‐tides: a 51‐kDa YLSKEWEDA‐ir polypeptide, CgA297–313, and CgA248–313. The latter predominated. The action of reserpine on both pancreastatin‐ and YLSKEWEDA‐ir was found to be largely inhibited by the protein synthesis inhibitor cycloheximide. The results show that treatment of isolated chromaffin cells with reserpine induces both the selective proteolytic processing and peptidyl‐glycine amidation of CgA and its derived fragments. As reserpine has a similar effect on proenkephalin in chromaffin cells, the results suggest that reserpine induces a general increase in the activity of the processing enzymes, partially by an increase in protein synthesis.

AB - Abstract: The effect of reserpine on the processing of the secretory granule protein chromogranin A (CgA) in isolated bovine adrenal chromaffin cells was investigated using two radioimmunoassays employing site‐specific antisera. The two antisera were directed against closely associated regions of the CgA molecule which would be exposed by specific processing: antiserum L331 was raised against the C‐terminus of the regulatory peptide pancreastatin, and the second anti‐serum, L300, was raised against the synthetic peptide [Tyr0]CgA306–313 (YLSKEWEDA), a sequence that lies immediately C‐terminal to pancreastatin and adjacent to a dibasic amino acid cleavage site. Chronic reserpine treatment of chromaffin cells produced a time‐ and dose‐dependent increase in processing, as demonstrated by an increase in pancreastatin‐ and YLSKEWEDA‐immunoreactivity (ir). The reserpine‐induced rise in pancreastatin‐ir was due predominantly to an increase in pancreastatin 1–47, whereas the rise in YLSKEWEDA‐ir was due to increases in three polypep‐tides: a 51‐kDa YLSKEWEDA‐ir polypeptide, CgA297–313, and CgA248–313. The latter predominated. The action of reserpine on both pancreastatin‐ and YLSKEWEDA‐ir was found to be largely inhibited by the protein synthesis inhibitor cycloheximide. The results show that treatment of isolated chromaffin cells with reserpine induces both the selective proteolytic processing and peptidyl‐glycine amidation of CgA and its derived fragments. As reserpine has a similar effect on proenkephalin in chromaffin cells, the results suggest that reserpine induces a general increase in the activity of the processing enzymes, partially by an increase in protein synthesis.

KW - Chromaffin cells

KW - Chromogranin A

KW - Pancreastatin

KW - Peptide processing

KW - Reserpine

U2 - 10.1111/j.1471-4159.1992.tb09338.x

DO - 10.1111/j.1471-4159.1992.tb09338.x

M3 - Journal article

C2 - 1737996

AN - SCOPUS:0026599196

VL - 58

SP - 877

EP - 883

JO - Journal of Neurochemistry

JF - Journal of Neurochemistry

SN - 0022-3042

IS - 3

ER -