Zachary T Schug1, Suresh K Joseph. 1. Department of Pathology, Cell Biology, and Anatomy, Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania 19107, USA.
Abstract
In previous studies we have suggested that spatial proximity of the C- and N-terminal domains of inositol 1,4,5-trisphosphate receptors (IP(3)Rs) may be critical for the channel gating mechanism. In the present study we have examined the sites of C-N interaction in more detail. We report that deletion mutations within the S4-S5 linker (amino acids 2418-2437) prevent co-immunoprecipitation of the C- and N-terminal domains, inhibit channel activity and enhance IP(3) binding. We also show that a region of the C-terminal tail (amino acids 2694-2721), predicted to be a coiled-coil, is also required for channel activity. Circular dichroism spectroscopy and gel filtration studies confirm that this region has a helical structure with the ability to form tetramers. We propose a model in which IP(3)-induced conformational changes in the N-terminal domain are mechanically transmitted to the opening of the pore through an attachment to the S4-S5 linker. The coiled-coil domain in the C-terminal tail may play a critical role in maintaining the structural integrity of the channel.
In previous studies we have suggested that spatial proximity of the C- and N-terminal domains of inositol 1,4,5-trisphosphate receptors (n class="Chemical">IP(3)Rs) may be critical for the channel gating mechanism. In the present study we have examined the sites of C-N interaction in more detail. We report that deletion mutations within the S4-S5 linker (amino acids 2418-2437) prevent co-immunoprecipitation of the C- and N-terminal domains, inhibit channel activity and enhance IP(3) binding. We also show that a region of the C-terminal tail (amino acids 2694-2721), predicted to be a coiled-coil, is also required for channel activity. Circular dichroism spectroscopy and gel filtration studies confirm that this region has a helical structure with the ability to form tetramers. We propose a model in which IP(3)-induced conformational changes in the N-terminal domain are mechanically transmitted to the opening of the pore through an attachment to the S4-S5 linker. The coiled-coil domain in the C-terminal tail may play a critical role in maintaining the structural integrity of the channel.
Authors: Georgia Anyatonwu; M Tariq Khan; Zachary T Schug; Paula C A da Fonseca; Edward P Morris; Suresh K Joseph Journal: J Biol Chem Date: 2010-06-08 Impact factor: 5.157
Authors: Kamil J Alzayady; Larry E Wagner; Rahul Chandrasekhar; Alina Monteagudo; Ronald Godiska; Gregory G Tall; Suresh K Joseph; David I Yule Journal: J Biol Chem Date: 2013-08-16 Impact factor: 5.157
Authors: Ana M Rossi; Andrew M Riley; Stephen C Tovey; Taufiq Rahman; Olivier Dellis; Emily J A Taylor; Valery G Veresov; Barry V L Potter; Colin W Taylor Journal: Nat Chem Biol Date: 2009-08-09 Impact factor: 15.040