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

Bokhovchuk, Fedir M and Bate, Neil and Kovalevskaya, Nadezhda V and Goult, Benjamin T and Spronk, Chris A E M and Vuister, Geerten W (2018) The Structural Basis of Calcium Dependent Inactivation of the Transient Receptor Potential Vanilloid 5 Channel. Biochemistry, . ISSN 1520-4995. (In press) (doi:https://doi.org/10.1021/acs.biochem.7b01287) (Full text available)

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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
Subjects: Q Science > QH Natural history > QH581.2 Cell Biology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Ben Goult
Date Deposited: 29 Mar 2018 11:49 UTC
Last Modified: 05 Apr 2018 14:23 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/66588 (The current URI for this page, for reference purposes)
Goult, Benjamin T: https://orcid.org/0000-0002-3438-2807
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