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The Structural Basis of Calcium Dependent Inactivation of the Transient Receptor Potential Vanilloid 5 Channel.

Bokhovchuk, Fedir M, Bate, Neil, Kovalevskaya, Nadezhda V, Goult, Benjamin T, Spronk, Chris A E M, Vuister, Geerten W (2018) The Structural Basis of Calcium Dependent Inactivation of the Transient Receptor Potential Vanilloid 5 Channel. Biochemistry, 57 . pp. 2623-2635. ISSN 1520-4995. (doi:10.1021/acs.biochem.7b01287) (KAR id:66588)

Abstract

The Transient Receptor Potential Vanilloid Channel subfamily member 5 (TRPV5) is a highly selective calcium ion channel predominately expressed in the kidney epithelium that plays an essential role in calcium reabsorption from renal infiltrate. In order to maintain Ca2+ homeostasis, TRPV5 possesses a tightly regulated negative feedback mechanism, where the ubiquitous Ca2+-binding protein Calmodulin (CaM) directly binds to the intracellular TRPV5 C-terminus, thus regulating TRPV5. Here we report on the characterisation of the TRPV5 C-terminal CaM binding site and its interaction with CaM at an atomistic level. We have solved the de novo solution structure of the TRPV5 C-terminus in complex with a CaM mutant, creating conditions that mimic the cellular basal Ca2+ state. We demonstrate that under these conditions the TRPV5 C-terminus is exclusively bound to the CaM C-lobe only, while conferring conformational freedom to the CaM N-lobe. We also show that at elevated calcium levels, additional interactions between the TRPV5 C-terminus and CaM N-lobe occur, resulting in formation of a tight 1:1 complex, effectively making the N-lobe the calcium sensor. Together, these data are consistent with, and support the novel model for Ca2+/CaM-dependent inactivation of TRPV channels as proposed by Bate et al. (Biochemistry, 2018, in press).

Item Type: Article
DOI/Identification number: 10.1021/acs.biochem.7b01287
Subjects: Q Science > QH Natural history > QH581.2 Cell Biology
Divisions: Divisions > Division of Natural Sciences > Biosciences
Depositing User: Ben Goult
Date Deposited: 29 Mar 2018 11:49 UTC
Last Modified: 09 Dec 2022 01:17 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/66588 (The current URI for this page, for reference purposes)

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