Competitive regulation of CaT-like-mediated Ca2+ entry by protein kinase C and calmodulin.
A finely tuned Ca(2+) signaling system is essential for cells to transduce extracellular stimuli, to regulate growth, and to differentiate. We have recently cloned CaT-like (CaT-L), a highly selective Ca(2+) channel closely related to the epithelial calcium channels (ECaC) and the calcium transport protein CaT1. CaT-L is expressed in selected ... exocrine tissues, and its expression also strikingly correlates with the malignancy of prostate cancer. The expression pattern and selective Ca(2+) permeation properties suggest an important function in Ca(2+) uptake and a role in tumor progression, but not much is known about the regulation of this subfamily of ion channels. We now demonstrate a biochemical and functional mechanism by which cells can control CaT-L activity. CaT-L is regulated by means of a unique calmodulin binding site, which, at the same time, is a target for protein kinase C-dependent phosphorylation. We show that Ca(2+)-dependent calmodulin binding to CaT-L, which facilitates channel inactivation, can be counteracted by protein kinase C-mediated phosphorylation of the calmodulin binding site.
Mesh Terms:
Amino Acid Sequence, Animals, Binding Sites, CHO Cells, Calcium, Calcium Channels, Calcium-Binding Proteins, Calmodulin, Cell Line, Cricetinae, Humans, Molecular Sequence Data, Phosphorylation, Protein Kinase C, Recombinant Fusion Proteins, TRPV Cation Channels
Amino Acid Sequence, Animals, Binding Sites, CHO Cells, Calcium, Calcium Channels, Calcium-Binding Proteins, Calmodulin, Cell Line, Cricetinae, Humans, Molecular Sequence Data, Phosphorylation, Protein Kinase C, Recombinant Fusion Proteins, TRPV Cation Channels
Proc. Natl. Acad. Sci. U.S.A.
Date: Mar. 13, 2001
PubMed ID: 11248124
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