Three-dimensional structure of recombinant type 1 inositol 1,4,5-trisphosphate receptor
Résumé
Inositol 1,4,5-trisphosphate receptors (IP3R) are the intracellular channels that mediate release of Ca2+ from the endoplasmic reticulum in response to the many stimuli that evoke IP3 formation. We characterized and purified type 1 IP3R heterologously expressed in Sf9 cells, and used the purified IP3R1 to determine its three-dimensional structure by electron microscopy and single particle analysis. Recombinant IP3R1 has four-fold symmetry with overall dimensions of about 19.5 x 19.5 x 17.5 nm3. It comprises a small domain, which is likely to include the pore, linked by slender bridges to a large cytoplasmic domain with four petal-like regions. Our structures of recombinant IP3R1 and native cerebellar IP3R have similar appearances and dimensions. The only notable difference is the absence of a central stigma-like domain from the cytoplasmic region of recombinant IP3R1. The first structure of a recombinant IP3R is an important step towards developing 3D structures of IP3R that better contribute to understanding the structural basis of IP3R activation.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...