6e2g
From Proteopedia
Cryo-EM structure of rat TRPV6 in complex with Calmodulin
Structural highlights
Disease[CALM1_HUMAN] The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of CPVT4. The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of LQT14. Function[TRPV6_RAT] Calcium selective cation channel probably involved in Ca(2+) uptake in various tissues, including Ca(2+) reabsorption in intestine. The channel is activated by low internal calcium level, probably including intracellular calcium store depletion, and the current exhibits an inward rectification. Inactivation includes both, a rapid Ca(2+)-dependent and a slower Ca(2+)-calmodulin-dependent mechanism, the latter may be regulated by phosphorylation. In vitro, is slowly inhibited by Mg(2+) in a voltage-independent manner. Heteromeric assembly with TRPV5 seems to modify channel properties. TRPV5-TRPV6 heteromultimeric concatemers exhibit voltage-dependent gating (By similarity).[UniProtKB:Q91WD2][UniProtKB:Q9H1D0][1] [CALM1_HUMAN] 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 (PubMed:16760425). Mediates calcium-dependent inactivation of CACNA1C (PubMed:26969752). Positively regulates calcium-activated potassium channel activity of KCNN2 (PubMed:27165696).[2] [3] [4] [5] Publication Abstract from PubMedCalcium (Ca(2+)) plays a major role in numerous physiological processes. Ca(2+) homeostasis is tightly controlled by ion channels, the aberrant regulation of which results in various diseases including cancers. Calmodulin (CaM)-mediated Ca(2+)-induced inactivation is an ion channel regulatory mechanism that protects cells against the toxic effects of Ca(2+) overload. We used cryo-electron microscopy to capture the epithelial calcium channel TRPV6 (transient receptor potential vanilloid subfamily member 6) inactivated by CaM. The TRPV6-CaM complex exhibits 1:1 stoichiometry; one TRPV6 tetramer binds both CaM lobes, which adopt a distinct head-to-tail arrangement. The CaM carboxyl-terminal lobe plugs the channel through a unique cation-pi interaction by inserting the side chain of lysine K115 into a tetra-tryptophan cage at the pore's intracellular entrance. We propose a mechanism of CaM-mediated Ca(2+)-induced inactivation that can be explored for therapeutic design. Mechanism of calmodulin inactivation of the calcium-selective TRP channel TRPV6.,Singh AK, McGoldrick LL, Twomey EC, Sobolevsky AI Sci Adv. 2018 Aug 15;4(8):eaau6088. doi: 10.1126/sciadv.aau6088. eCollection 2018, Aug. PMID:30116787[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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