PT  - JOURNAL ARTICLE
AU  - Taylor E.T. Hughes
AU  - Ruth A. Pumroy
AU  - Aysenur Torun Yazici
AU  - Marina A. Kasimova
AU  - Edwin C. Fluck
AU  - Kevin W. Huynh
AU  - Amrita Samanta
AU  - Sudheer Mulugu
AU  - Z. Hong Zhou
AU  - Vincenzo Carnevale
AU  - Tibor Rohacs
AU  - Vera Y. Moiseenkova-Bell
TI  - Structural insights on TRPV5 gating by endogenous modulators
AID  - 10.1101/338798
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 338798
4099  - http://biorxiv.org/content/early/2018/07/31/338798.short
4100  - http://biorxiv.org/content/early/2018/07/31/338798.full
AB  - TRPV5 is a transient receptor potential channel involved in calcium reabsorption. Here we investigate the interaction of two endogenous modulators with TRPV5. Both phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and calmodulin (CaM) have been shown to directly bind to TRPV5 and activate or inactivate the channel, respectively. Using cryo-electron microscopy (cryo-EM), we determined TRPV5 structures in the presence of dioctanoyl PI(4,5)P2 and CaM. The PI(4,5)P2 structure revealed a novel binding site between the N-linker, S4-S5 linker and S6 helix of TRPV5. These interactions with PI(4,5)P2 induce conformational rearrangements in the lower gate, opening the channel. The CaM structure revealed two TRPV5 C-terminal peptides anchoring a single CaM molecule and that calcium inhibition is mediated through a cation-π interaction between Lys116 on the C-lobe of calcium-activated CaM and Trp583 at the intracellular gate of TRPV5. Overall, this investigation provides insight into the endogenous modulation of TRPV5, which has the potential to guide drug discovery.