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From Proteopedia
Structure of Transient Receptor Potential (TRP) channel TRPV6 in the presence of barium
Structural highlights
FunctionTRPV6_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] Publication Abstract from PubMedPrecise regulation of calcium homeostasis is essential for many physiological functions. The Ca(2+)-selective transient receptor potential (TRP) channels TRPV5 and TRPV6 play vital roles in calcium homeostasis as Ca(2+) uptake channels in epithelial tissues. Detailed structural bases for their assembly and Ca(2+) permeation remain obscure. Here we report the crystal structure of rat TRPV6 at 3.25 A resolution. The overall architecture of TRPV6 reveals shared and unique features compared with other TRP channels. Intracellular domains engage in extensive interactions to form an intracellular 'skirt' involved in allosteric modulation. In the K(+) channel-like transmembrane domain, Ca(2+) selectivity is determined by direct coordination of Ca(2+) by a ring of aspartate side chains in the selectivity filter. On the basis of crystallographically identified cation-binding sites at the pore axis and extracellular vestibule, we propose a Ca(2+) permeation mechanism. Our results provide a structural foundation for understanding the regulation of epithelial Ca(2+) uptake and its role in pathophysiology. Crystal structure of the epithelial calcium channel TRPV6.,Saotome K, Singh AK, Yelshanskaya MV, Sobolevsky AI Nature. 2016 Jun 13;534(7608):506-11. doi: 10.1038/nature17975. PMID:27296226[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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