1. G protein β subunits regulate Ca v 3.3 T-type channel activity and current kinetics via interaction with the Ca v 3.3 C-terminus.
- Author
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Jeong S, Lee BY, Rhee JS, and Lee JH
- Subjects
- Animals, Humans, Rats, Calcium Channels, R-Type, Cation Transport Proteins, GTP-Binding Protein gamma Subunits metabolism, GTP-Binding Protein gamma Subunits genetics, GTP-Binding Protein gamma Subunits chemistry, HEK293 Cells, Kinetics, Patch-Clamp Techniques, Protein Binding, Calcium Channels, T-Type metabolism, Calcium Channels, T-Type genetics, Calcium Channels, T-Type chemistry, GTP-Binding Protein beta Subunits metabolism, GTP-Binding Protein beta Subunits genetics, GTP-Binding Protein beta Subunits chemistry
- Abstract
Ca
2+ influx through Cav 3.3 T-type channel plays crucial roles in neuronal excitability and is subject to regulation by various signaling molecules. However, our understanding of the partners of Cav 3.3 and the related regulatory pathways remains largely limited. To address this quest, we employed the rat Cav 3.3 C-terminus as bait in yeast-two-hybrid screenings of a cDNA library, identifying rat Gβ2 as an interaction partner. Subsequent assays revealed that the interaction of Gβ2 subunit was specific to the Cav 3.3 C-terminus. Through systematic dissection of the C-terminus, we pinpointed a 22 amino acid sequence (amino acids 1789-1810) as the Gβ2 interaction site. Coexpression studies of rat Cav 3.3 with various Gβγ compositions were conducted in HEK-293 cells. Patch clamp recordings revealed that coexpression of Gβ2 γ2 reduced Cav 3.3 current density and accelerated inactivation kinetics. Interestingly, the effects were not unique to Gβ2 γ2, but were mimicked by Gβ2 alone as well as other Gβγ dimers, with similar potencies. Deletion of the Gβ2 interaction site abolished the effects of Gβ2 γ2 . Importantly, these Gβ2 effects were reproduced in human Cav 3.3. Overall, our findings provide evidence that Gβ(γ) complexes inhibit Cav 3.3 channel activity and accelerate the inactivation kinetics through the Gβ interaction with the Cav 3.3 C-terminus., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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