ジャーナル: Nat Struct Mol Biol / 年: 2017 タイトル: Molecular insights into lipid-assisted Ca regulation of the TRP channel Polycystin-2. 著者: Martin Wilkes / M Gregor Madej / Lydia Kreuter / Daniel Rhinow / Veronika Heinz / Silvia De Sanctis / Sabine Ruppel / Rebecca M Richter / Friederike Joos / Marina Grieben / Ashley C W Pike / ...著者: Martin Wilkes / M Gregor Madej / Lydia Kreuter / Daniel Rhinow / Veronika Heinz / Silvia De Sanctis / Sabine Ruppel / Rebecca M Richter / Friederike Joos / Marina Grieben / Ashley C W Pike / Juha T Huiskonen / Elisabeth P Carpenter / Werner Kühlbrandt / Ralph Witzgall / Christine Ziegler / 要旨: Polycystin-2 (PC2), a calcium-activated cation TRP channel, is involved in diverse Ca signaling pathways. Malfunctioning Ca regulation in PC2 causes autosomal-dominant polycystic kidney disease. Here ...Polycystin-2 (PC2), a calcium-activated cation TRP channel, is involved in diverse Ca signaling pathways. Malfunctioning Ca regulation in PC2 causes autosomal-dominant polycystic kidney disease. Here we report two cryo-EM structures of distinct channel states of full-length human PC2 in complex with lipids and cations. The structures reveal conformational differences in the selectivity filter and in the large exoplasmic domain (TOP domain), which displays differing N-glycosylation. The more open structure has one cation bound below the selectivity filter (single-ion mode, PC2), whereas multiple cations are bound along the translocation pathway in the second structure (multi-ion mode, PC2). Ca binding at the entrance of the selectivity filter suggests Ca blockage in PC2, and we observed density for the Ca-sensing C-terminal EF hand in the unblocked PC2 state. The states show altered interactions of lipids with the pore loop and TOP domain, thus reflecting the functional diversity of PC2 at different locations, owing to different membrane compositions.
we used for comparative structure modeling TRPA1 (pdb entry code 3J9P) as template for S1 and S3-S5, TRPV1 (pdb entry code 3J5Q) for S5-S6, and the TRPV2 (pdb entry code 5AN8) fitted best for S2-S3 to obtain an initial model. The soluble domain was build based on pdbID: 5K47. But we had no search model for molecular replacement. Although we had a good idea what the architecture would be like, we build the model de novo with COOT.
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PDB-5mkf: cryoEM Structure of Polycystin-2 in complex with calcium and lipids