PMID: 26894959
Authors:
Das S, Gilchrist J, Bosmans F, Van Petegem F
Title:
Binary architecture of the Nav1.2-beta2 signaling complex.
Journal:
Elife. 2016 Feb 19;5. pii: e10960. doi: 10.7554/eLife.10960.
Abstract:
To investigate the mechanisms by which beta-subunits influence Nav channel function, we solved the crystal structure of the beta2 extracellular domain at 1.35A. We combined these data with known bacterial Nav channel structural insights and novel functional studies to determine the interactions of specific residues in beta2 with Nav1.2. We identified a flexible loop formed by (72)Cys and (75)Cys, a unique feature among the four beta-subunit isoforms. Moreover, we found that (55)Cys helps to determine the influence of beta2 on Nav1.2 toxin susceptibility. Further mutagenesis combined with the use of spider toxins reveals that (55)Cys forms a disulfide bond with (910)Cys in the Nav1.2 domain II pore loop, thereby suggesting a 1:1 stoichiometry. Our results also provide clues as to which disulfide bonds are formed between adjacent Nav1.2 (912/918)Cys residues. The concepts emerging from this work will help to form a model reflecting the beta-subunit location in a Nav channel complex.