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Updated: Aug 26, 2026

Single-Cell Calcium Imaging for Studying the Activation of Calcium Ion Channels
Published on: December 13, 2024
RACK1 binds to inositol 1,4,5-trisphosphate receptors and mediates Ca2+ release
Randen L Patterson1, Damian B van Rossum, Roxanne K Barrow
1Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Abstract:
RACK1 is not a G protein but closely resembles the heterotrimeric Gbeta-subunit. RACK1 serves as a scaffold, linking protein kinase C to its substrates. We demonstrate that RACK1 physiologically binds inositol 1,4,5-trisphosphate receptors and regulates Ca2+ release by enhancing inositol 1,4,5-trisphosphate receptor binding affinity for inositol 1,4,5-trisphosphate. Overexpression of RACK1 or depletion of RACK1 by interference RNA markedly augments or diminishes Ca2+ release, respectively, without affecting Ca2+ entry. These findings establish RACK1 as a physiologic mediator of agonist-induced Ca2+ release.
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