5k47
From Proteopedia
CryoEM structure of the human Polycystin-2/PKD2 TRP channel
Structural highlights
Disease[PKD2_HUMAN] Defects in PKD2 are the cause of polycystic kidney disease 2 (PKD2) [MIM:613095]. PKD2 is a disorder characterized by progressive formation and enlargement of cysts in both kidneys, typically leading to end-stage renal disease in adult life. Cysts also occurs in the liver and other organs. It represents approximately 15% of the cases of autosomal dominant polycystic kidney disease. PKD2 is clinically milder than PKD1 but it has a deleterious impact on overall life expectancy.[1] [2] [3] [4] [5] [6] [7] [8] [9] Function[PKD2_HUMAN] Involved in fluid-flow mechanosensation by the primary cilium in renal epithelium (By similarity). PKD1 and PKD2 may function through a common signaling pathway that is necessary for normal tubulogenesis (By similarity). Acts as a regulator of cilium length, together with PKD1 (By similarity). The dynamic control of cilium length is essential in the regulation of mechanotransductive signaling. The cilium length response creates a negative feedback loop whereby fluid shear-mediated deflection of the primary cilium, which decreases intracellular cAMP, leads to cilium shortening and thus decreases flow-induced signaling (By similarity). Functions as a calcium permeable cation channel. Publication Abstract from PubMedMutations in either polycystin-1 (PC1 or PKD1) or polycystin-2 (PC2, PKD2 or TRPP1) cause autosomal-dominant polycystic kidney disease (ADPKD) through unknown mechanisms. Here we present the structure of human PC2 in a closed conformation, solved by electron cryomicroscopy at 4.2-A resolution. The structure reveals a novel polycystin-specific 'tetragonal opening for polycystins' (TOP) domain tightly bound to the top of a classic transient receptor potential (TRP) channel structure. The TOP domain is formed from two extensions to the voltage-sensor-like domain (VSLD); it covers the channel's endoplasmic reticulum lumen or extracellular surface and encloses an upper vestibule, above the pore filter, without blocking the ion-conduction pathway. The TOP-domain fold is conserved among the polycystins, including the homologous channel-like region of PC1, and is the site of a cluster of ADPKD-associated missense variants. Extensive contacts among the TOP-domain subunits, the pore and the VSLD provide ample scope for regulation through physical and chemical stimuli. Structure of the polycystic kidney disease TRP channel Polycystin-2 (PC2).,Grieben M, Pike AC, Shintre CA, Venturi E, El-Ajouz S, Tessitore A, Shrestha L, Mukhopadhyay S, Mahajan P, Chalk R, Burgess-Brown NA, Sitsapesan R, Huiskonen JT, Carpenter EP Nat Struct Mol Biol. 2016 Dec 19. doi: 10.1038/nsmb.3343. PMID:27991905[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Arrowsmith, C H | Bountra, C | Burgess-Brown, N A | Carpenter, E P | Chalk, R | Edwards, A M | Grieben, M | Huiskonen, J T | Mahajan, P | Mukhopadhyay, S | Pike, A C.W | Structural genomic | Shintre, C A | Shrestha, L | Tessitore, A | Ion channel | Polycystic kidney disease | Sgc | Transient receptor potential channel | Transport protein
