2OCY

Complex of the guanine exchange factor Sec2p and the Rab GTPase Sec4p

Summary for 2OCY

• Entry DOI: 10.2210/pdb2ocy/pdb
• Related: 1G16 1G17
• Descriptor: Rab guanine nucleotide exchange factor SEC2, Ras-related protein SEC4 (2 entities in total)
• Functional Keywords: rab, gef, guanine exchange factor, coiled-coil, endocytosis-exocytosis complex, endocytosis/exocytosis
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Cellular location: Bud neck : P17065; Cytoplasmic vesicle, secretory vesicle membrane; Lipid-anchor; Cytoplasmic side: P07560
• Total number of polymer chains: 3
• Total formula weight: 55329.02

Authors

Reinisch, K.M.,Dong, G. (deposition date: 2006-12-21, release date: 2007-02-27, Last modification date: 2024-11-13)

Primary citation

Dong, G.,Medkova, M.,Novick, P.,Reinisch, K.M.
A Catalytic Coiled Coil: Structural Insights into the Activation of the Rab GTPase Sec4p by Sec2p.
Mol.Cell, 25:455-462, 2007

PubMed Abstract: Rab GTPases, the largest subgroup in the superfamily of Ras-like GTPases, play regulatory roles in multiple steps of intracellular vesicle trafficking. They are activated by guanine nucleotide exchange factors (GEFs), which catalyze the interconversion of the GDP-bound, or inactive, form of Rab to the GTP-bound, or active, form. Relatively little is known of the mechanisms by which GEFs activate Rabs. Here, we present the crystal structure of the GEF domain of Sec2p in complex with its Rab partner Sec4p. The Sec2p GEF domain is a 220 Angstroms long coiled coil, striking in its simplicity and in the use of the coiled-coil motif for catalysis. The structure suggests a mechanism whereby Sec2p induces extensive structural rearrangements in the Sec4p switch regions and phosphate-binding loop that are incompatible with nucleotide binding. We show that Sec2p is specific for Sec4p and that specificity determinants reside in the two switch regions of Sec4p.

PubMed: 17289591
DOI: 10.1016/j.molcel.2007.01.013

Experimental method

X-RAY DIFFRACTION (3.3 Å)