An intramolecular salt bridge drives the soluble domain of GTP-bound atlastin into the postfusion conformation.

ABSTRACT: Endoplasmic reticulum (ER) network branching requires homotypic tethering and fusion of tubules mediated by the atlastin (ATL) guanosine triphosphatase (GTPase). Recent structural studies on the ATL soluble domain reveal two dimeric conformers proposed to correspond to a tethered prefusion state and a postfusion state. How the prefusion conformer transitions to the postfusion conformer is unknown. In this paper, we identify an intramolecular salt bridge mediated by two residues outside the GTPase domain near the point of rotation that converts the prefusion dimer to the postfusion state. Charge reversal of either residue blocked ER network branching, whereas a compensatory charge reversal to reestablish electrostatic attraction restored function. In vitro assays using the soluble domain re

SUBMITTER: Morin-Leisk J 

PROVIDER: S-EPMC3257528 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature