Chromogranin B-induced secretory granule biogenesis: comparison with the similar role of chromogranin A.
The two major proteins of secretory granules of secretory cells, chromogranins A (CGA) and B (CGB), have previously been proposed to play key roles in secretory granule biogenesis. Recently, CGA was reported to play an on/off switch role for secretory granule biogenesis. In the present study we found CGB being more effective than CGA in inducing secretory granule formation in non-neuroendocrine NIH3T3 and COS-7 cells. The mean number of dense core granules formed/cell of CGA-transfected NIH3T3 cells was 2.51, whereas that of CGB-transfected cells was 4.02, indicating the formation of 60% more granules in the CGB-transfected cells. Similarly, there were 55% more dense core granules formed in the CGB-transfected COS-7 cells than in the CGA-transfected cells. Moreover, transfection of CGA- and CGB-short interfering RNA (siRNA) into neuroendocrine PC12 cells not only decreased the amount of CGA and CGB expressed but also reduced the number of secretory granules by 41 and 78%, respectively, further suggesting the importance of CGB expression in secretory granule formation.
Huh
Yang Hoon
YH
Department of Biochemistry, Inha University College of Medicine, Jung Gu, Incheon 400-712, Korea.
Jeon
Soung Hoo
SH
Yoo
Seung Hyun
SH
D000818:Animals; D019556:COS Cells; D053379:Chromogranin A; D053378:Chromogranin B; D002864:Chromogranins / Q000494:pharmacology / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D015151:Immunoblotting; D007150:Immunohistochemistry; D051379:Mice; D008854:Microscopy, Electron; D041681:NIH 3T3 Cells; D016716:PC12 Cells; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D022142:Secretory Vesicles / Q000187:drug effects*; D014162:Transfection
D053379:Chromogranin A; D053378:Chromogranin B; D002864:Chromogranins; D034741:RNA, Small Interfering; C506155:chromogranin A, mouse; C506153:chromogranin A, rat; C506137:chromogranin B, mouse; C506140:chromogranin B, rat