Download MendeleyThe Structural Basis of Calcium-Dependent Inactivation of the Transient Receptor Potential Vanilloid 5 Channel.
Bokhovchuk, F.M., Bate, N., Kovalevskaya, N.V., Goult, B.T., Spronk, C.A.E.M., Vuister, G.W.(2018) Biochemistry 57: 2623-2635
- PubMed: 29584409
- DOI: https://doi.org/10.1021/acs.biochem.7b01287
- Primary Citation of Related Structures:
5OEO - PubMed 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 Ca 2+ homeostasis, TRPV5 possesses a tightly regulated negative feedback mechanism, where the ubiquitous Ca 2+ binding protein calmodulin (CaM) directly binds to the intracellular TRPV5 C-terminus, thus regulating TRPV5. Here we report on the characterization 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 Ca 2+ state. We demonstrate that under these conditions the TRPV5 C-terminus is exclusively bound to the CaM C-lobe only, while it confers 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 Ca 2+ /CaM-dependent inactivation of TRPV channels as proposed by Bate and co-workers [ Bate , N. , et al. ( 2018 ) Biochemistry , ( 57), DOI: 10.1021/acs.biochem.7b01286 ].
Organizational Affiliation:
Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology , University of Leicester , Lancaster Road , Leicester LE1 9HN , United Kingdom.
