A new functional domain of guanine nucleotide dissociation inhibitor (alpha-GDI) involved in Rab recycling.Luan, P., Heine, A., Zeng, K., Moyer, B., Greasely, S.E., Kuhn, P., Balch, W.E., Wilson, I.A.
(2000) Traffic 1: 270-281
- PubMed: 11208110
- DOI: https://doi.org/10.1034/j.1600-0854.2000.010309.x
- Primary Citation of Related Structures:
- PubMed Abstract:
Guanine nucleotide dissociation inhibitor (GDI) is a 55-kDa protein that functions in vesicular membrane transport to recycle Rab GTPases. We have now determined the crystal structure of bovine alpha-GDI at ultra-high resolution (1.04 A). Refinement at this resolution highlighted a region with high mobility of its main-chain residues. This corresponded to a surface loop in the primarily alpha-helical domain II at the base of alpha-GDI containing the previously uncharacterized sequence-conserved region (SCR) 3A. Site-directed mutagenesis showed that this mobile loop plays a crucial role in binding of GDI to membranes and extraction of membrane-bound Rab. This domain, referred to as the mobile effector loop, in combination with Rab-binding residues found in the multi-sheet domain I at the apex of alpha-GDI may provide flexibility for recycling of diverse Rab GTPases. We propose that conserved residues in domains I and II synergize to form the functional face of GDI, and that domain II mediates a critical step in Rab recycling during vesicle fusion.
Department of Molecular Biology, Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA.