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Updated: Feb 19, 2026

Single-Cell Calcium Imaging for Studying the Activation of Calcium Ion Channels
Published on: December 13, 2024
Inositol 1,4,5-trisphosphate receptor/Ca(2+) channel modulatory role of chromogranins A and B
Seung Hyun Yoo1, Seung Ho So, Yang Hoon Huh
1National Creative Research Initiative Center for Secretory Granule Research, Department of Biochemistry, Inha University College of Medicine,Shinheungdong 3ga, Jung Gu, Incheon 400-712, Korea. shyoo@inha.ac.kr
Abstract:
The secretory granules function as the major IP(3)-sensitive intracellular Ca(2+) store of secretory cells. Recently it was found that the secretory granules contain three isoforms of inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca(2+) channels and high-capacity, low-affinity Ca(2+) storage proteins chromogranins A (CgA) and B (CgB). The IP(3)R/Ca(2+) channel was shown to directly interact with CgA and CgB at the intragranular pH 5.5, and this coupling led to modulation of the IP(3)R/Ca(2+) channel activity by the coupled chromogranins. These results provide the molecular structural basis of the IP(3)-mediated Ca(2+) release mechanism of secretory granules.
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