| Structural highlights
Function
ITPR1_MOUSE Intracellular channel that mediates calcium release from the endoplasmic reticulum following stimulation by inositol 1,4,5-trisphosphate. Plays a role in ER stress-induced apoptosis. Cytoplasmic calcium released from the ER triggers apoptosis by the activation of CaM kinase II, eventually leading to the activation of downstream apoptosis pathways.[1] [2] [3]
Publication Abstract from PubMed
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is an IP3-gated ion channel that releases calcium ions (Ca2+) from the endoplasmic reticulum. The IP3-binding sites in the large cytosolic domain are distant from the Ca2+ conducting pore, and the allosteric mechanism of how IP3 opens the Ca2+ channel remains elusive. Here, we identify a long-range gating mechanism uncovered by channel mutagenesis and X-ray crystallography of the large cytosolic domain of mouse type 1 IP3R in the absence and presence of IP3 Analyses of two distinct space group crystals uncovered an IP3-dependent global translocation of the curvature alpha-helical domain interfacing with the cytosolic and channel domains. Mutagenesis of the IP3R channel revealed an essential role of a leaflet structure in the alpha-helical domain. These results suggest that the curvature alpha-helical domain relays IP3-controlled global conformational dynamics to the channel through the leaflet, conferring long-range allosteric coupling from IP3 binding to the Ca2+ channel.
IP3-mediated gating mechanism of the IP3 receptor revealed by mutagenesis and X-ray crystallography.,Hamada K, Miyatake H, Terauchi A, Mikoshiba K Proc Natl Acad Sci U S A. 2017 May 2;114(18):4661-4666. doi:, 10.1073/pnas.1701420114. Epub 2017 Apr 17. PMID:28416699[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Furuichi T, Yoshikawa S, Miyawaki A, Wada K, Maeda N, Mikoshiba K. Primary structure and functional expression of the inositol 1,4,5-trisphosphate-binding protein P400. Nature. 1989 Nov 2;342(6245):32-8. PMID:2554142 doi:http://dx.doi.org/10.1038/342032a0
- ↑ Li G, Mongillo M, Chin KT, Harding H, Ron D, Marks AR, Tabas I. Role of ERO1-alpha-mediated stimulation of inositol 1,4,5-triphosphate receptor activity in endoplasmic reticulum stress-induced apoptosis. J Cell Biol. 2009 Sep 21;186(6):783-92. doi: 10.1083/jcb.200904060. Epub 2009 Sep, 14. PMID:19752026 doi:http://dx.doi.org/10.1083/jcb.200904060
- ↑ Yamazaki H, Chan J, Ikura M, Michikawa T, Mikoshiba K. Tyr-167/Trp-168 in type 1/3 inositol 1,4,5-trisphosphate receptor mediates functional coupling between ligand binding and channel opening. J Biol Chem. 2010 Nov 12;285(46):36081-91. doi: 10.1074/jbc.M110.140129. Epub, 2010 Sep 2. PMID:20813840 doi:http://dx.doi.org/10.1074/jbc.M110.140129
- ↑ Hamada K, Miyatake H, Terauchi A, Mikoshiba K. IP3-mediated gating mechanism of the IP3 receptor revealed by mutagenesis and X-ray crystallography. Proc Natl Acad Sci U S A. 2017 May 2;114(18):4661-4666. doi:, 10.1073/pnas.1701420114. Epub 2017 Apr 17. PMID:28416699 doi:http://dx.doi.org/10.1073/pnas.1701420114
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