2a05 | pdb_00002a05

The cysteine-rich secretory protein domain of Tpx-1 is related to ion channel toxins and regulates Ryanodine receptor Ca2+ signaling

spinqualitylabelsall models 2a05, 23 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2a05 is a 1 chain structure with sequence from Lk3 transgenic mice. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [CRIS2_MOUSE] May regulate some ion channels' activity and therebye regulate calcium fluxes during sperm capacitation. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The cysteine-rich secretory proteins (Crisp) are predominantly found in the mammalian male reproductive tract as well as in the venom of reptiles. Crisps are two domain proteins with a structurally similar yet evolutionary diverse N-terminal domain and a characteristic cysteine-rich C-terminal domain, which we refer to as the Crisp domain. We presented the NMR solution structure of the Crisp domain of mouse Tpx-1, and we showed that it contains two subdomains, one of which has a similar fold to the ion channel regulators BgK and ShK. Furthermore, we have demonstrated for the first time that the ion channel regulatory activity of Crisp proteins is attributed to the Crisp domain. Specifically, the Tpx-1 Crisp domain inhibited cardiac ryanodine receptor (RyR) 2 with an IC(50) between 0.5 and 1.0 microM and activated the skeletal RyR1 with an AC(50) between 1 and 10 microM when added to the cytoplasmic domain of the receptor. This activity was nonvoltage-dependent and weakly voltage-dependent, respectively. Furthermore, the Tpx-1 Crisp domain activated both RyR forms at negative bilayer potentials and showed no effect at positive bilayer potentials when added to the luminal domain of the receptor. These data show that the Tpx-1 Crisp domain on its own can regulate ion channel activity and provide compelling evidence for a role for Tpx-1 in the regulation of Ca(2+) fluxes observed during sperm capacitation. The cysteine-rich secretory protein domain of Tpx-1 is related to ion channel toxins and regulates ryanodine receptor Ca2+ signaling.,Gibbs GM, Scanlon MJ, Swarbrick J, Curtis S, Gallant E, Dulhunty AF, O'Bryan MK J Biol Chem. 2006 Feb 17;281(7):4156-63. Epub 2005 Dec 9. PMID:16339766 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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