Structure of the inositol 1,4,5-trisphosphate receptor binding core in complex with its ligand
Abstract
In a variety of cells, the Ca2+ signalling process is mediated by the endoplasmic-reticulum-membrane-associated Ca2+ release channel, inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R). Being ubiquitous and present in organisms ranging from humans to Caenorhabditis elegans, InsP3R has a vital role in the control of cellular and physiological processes as diverse as cell division, cell proliferation, apoptosis, fertilization, development, behaviour, memory and learning. Mouse type I InsP3R (InsP3R1), found in high abundance in cerebellar Purkinje cells, is a polypeptide with three major functionally distinct regions: the amino-terminal InsP3-binding region, the central modulatory region and the carboxy-terminal channel region. Here we present a 2.2-Å crystal structure of the InsP3-binding core of mouse InsP3R1 in complex with InsP3. The asymmetric, boomerang-like structure consists of an N-terminal β-trefoil domain and a C-terminal α-helical domain containing an `armadillo repeat'-like fold. The cleft formed by the two domains exposes a cluster of arginine and lysine residues that coordinate the three phosphoryl groups of InsP3. Putative Ca2+-binding sites are identified in two separate locations within the InsP3-binding core.
- Publication:
-
Nature
- Pub Date:
- December 2002
- DOI:
- 10.1038/nature01268
- Bibcode:
- 2002Natur.420..696B