Crystal structure of inositol 1,4,5-trisphosphate receptor large cytosolic domain with inositol 1,4,5-trisphosphateCrystal structure of inositol 1,4,5-trisphosphate receptor large cytosolic domain with inositol 1,4,5-trisphosphate

Structural highlights

5gug is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

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.

References

  1. 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
  2. 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
  3. 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
  4. 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

5gug, resolution 7.40Å

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