6dmw
From Proteopedia
Calmodulin-bound full-length rbTRPV5
Structural highlights
Function[TRPV5_RABIT] Constitutively active calcium selective cation channel thought to be involved in Ca(2+) reabsorption in kidney and intestine (PubMed:12574114). Required for normal Ca(2+) reabsorption in the kidney distal convoluted tubules (By similarity). The channel is activated by low internal calcium level and the current exhibits an inward rectification (By similarity). A Ca(2+)-dependent feedback regulation includes fast channel inactivation and slow current decay (By similarity). Heteromeric assembly with TRPV6 seems to modify channel properties. TRPV5-TRPV6 heteromultimeric concatemers exhibit voltage-dependent gating (PubMed:12574114).[UniProtKB:P69744][UniProtKB:Q9NQA5][1] [2] [3] [CALM1_RAT] Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis. Mediates calcium-dependent inactivation of CACNA1C. Positively regulates calcium-activated potassium channel activity of KCNN2.[UniProtKB:P62158] Publication Abstract from PubMedTRPV5 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 reveals a 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 reveals two TRPV5 C-terminal peptides anchoring a single CaM molecule and that calcium inhibition is mediated through a cation-pi 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. Structural insights on TRPV5 gating by endogenous modulators.,Hughes TET, Pumroy RA, Yazici AT, Kasimova MA, Fluck EC, Huynh KW, Samanta A, Molugu SK, Zhou ZH, Carnevale V, Rohacs T, Moiseenkova-Bell VY Nat Commun. 2018 Oct 10;9(1):4198. doi: 10.1038/s41467-018-06753-6. PMID:30305626[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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