Document Detail

Secretory granules in inositol 1,4,5-trisphosphate-dependent Ca2+ signaling in the cytoplasm of neuroendocrine cells.
MedLine Citation:
PMID:  19837865     Owner:  NLM     Status:  MEDLINE    
Of all the intracellular organelles, secretory granules contain by far the highest calcium concentration; secretory granules of typical neuroendocrine chromaffin cells contain approximately 40 mM Ca(2+) and occupy approximately 20% cell volume, accounting for >60% of total cellular calcium. They also contain the majority of cellular inositol 1,4,5-trisphosphate receptors (IP(3)Rs) in addition to the presence of >2 mM of chromogranins A and B that function as high-capacity, low-affinity Ca(2+) storage proteins. Chromogranins A and B also interact with the IP(3)Rs and activate the IP(3)R/Ca(2+) channels. In experiments with both neuroendocrine PC12 and nonneuroendocrine NIH3T3 cells, in which the number of secretory granules present was changed by either suppression or induction of secretory granule formation, secretory granules were demonstrated to account for >70% of the IP(3)-induced Ca(2+) releases in the cytoplasm. Moreover, the IP(3) sensitivity of secretory granule IP(3)R/Ca(2+) channels is at least approximately 6- to 7-fold more sensitive than those of the endoplasmic reticulum, thus enabling secretory granules to release Ca(2+) ahead of the endoplasmic reticulum. Further, there is a direct correlation between the number of secretory granules and the IP(3) sensitivity of cytoplasmic IP(3)R/Ca(2+) channels and the increased ratio of IP(3)-induced cytoplasmic Ca(2+) release, highlighting the importance of secretory granules in the IP(3)-dependent Ca(2+) signaling. Given that secretory granules are present in all secretory cells, these results presage critical roles of secretory granules in the control of cytoplasmic Ca(2+) concentrations in other secretory cells.-Yoo, S. H. Secretory granules in inositol 1,4,5-trisphosphate-dependent Ca(2+) signaling in the cytoplasm of neuroendocrine cells.
Seung Hyun Yoo
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Review     Date:  2009-10-16
Journal Detail:
Title:  FASEB journal : official publication of the Federation of American Societies for Experimental Biology     Volume:  24     ISSN:  1530-6860     ISO Abbreviation:  FASEB J.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-02     Completed Date:  2010-05-11     Revised Date:  2012-02-15    
Medline Journal Info:
Nlm Unique ID:  8804484     Medline TA:  FASEB J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  653-64     Citation Subset:  IM    
Department of Biochemistry, Inha University School of Medicine, Jung Gu, Incheon 400-712, Korea.
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MeSH Terms
Calcium / metabolism
Calcium Signaling / drug effects*
Chromogranin A / metabolism
Chromogranin B / metabolism
Cytoplasm / drug effects,  metabolism*
Inositol 1,4,5-Trisphosphate / pharmacology*
Inositol 1,4,5-Trisphosphate Receptors / metabolism
Models, Biological
Neurosecretory Systems / drug effects,  metabolism*
Secretory Vesicles / drug effects,  metabolism*
Reg. No./Substance:
0/Chromogranin A; 0/Chromogranin B; 0/Inositol 1,4,5-Trisphosphate Receptors; 7440-70-2/Calcium; 85166-31-0/Inositol 1,4,5-Trisphosphate

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