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Institut de Biologie StructuraleGrenoble / France

Contact person(s) related to this article / SKOUFIAS Dimitrios

Kinesin-associated proteins

The human neuronal protein Rab6B

The Rab small G protein family plays important roles in eukaryotes as regulators of vesicle traffic. In Rab proteins, the hydrolysis of GTP to GDP is coupled to the association with and dissociation from membranes. Conformational changes related to their different nucleotide states determine their effector specificity. We solved the crystal structure of human neuronal Rab6B in its “inactive” (with bound MgGDP) and “active” (MgGTPγS-bound) form to 2.3 Å and 1.8 Å, respectively. Both crystallized in the space group P212121 with similar cell parameters allowing us the comparison of both structures without packing artifacts. Conformational changes between the inactive GDP and active GTP-like state are observed mainly in the switch I and switch II regions, confirming their role as a molecular switch. Compared to other Rab proteins, additional changes are observed in the Rab6 subfamily specific RabSF3 region that might contribute to the specificity of Rab6 for its different effector proteins, which would include the kinesin RabK6.


Garcia-Saez, I., Tcherniuk, S. and Kozielski, F. (2006). The structure of human neuronal Rab6B in the active and inactive form. Acta Crystallogr. D Biol. Crystallogr. D62, 725-733