Download MendeleyStructural basis of Rab5-Rabaptin5 interaction in endocytosis
Zhu, G., Zhai, P., Liu, J., Terzyan, S., Li, G., Zhang, X.C.(2004) Nat Struct Mol Biol 11: 975-983
- PubMed: 15378032
- DOI: https://doi.org/10.1038/nsmb832
- Primary Citation of Related Structures:
1TU3, 1TU4 - PubMed Abstract:
Rab5 is a small GTPase that regulates early endosome fusion. We present here the crystal structure of the Rab5 GTPase domain in complex with a GTP analog and the C-terminal domain of effector Rabaptin5. The proteins form a dyad-symmetric Rab5-Rabaptin5(2)-Rab5 ternary complex with a parallel coiled-coil Rabaptin5 homodimer in the middle. Two Rab5 molecules bind independently to the Rabaptin5 dimer using their switch and interswitch regions. The binding does not involve the Rab complementarity-determining regions. We also present the crystal structures of two distinct forms of GDP-Rab5 complexes, both of which are incompatible with Rabaptin5 binding. One has a dislocated and disordered switch I but a virtually intact switch II, whereas the other has its beta-sheet and both switch regions reorganized. Biochemical and functional analyses show that the crystallographically observed Rab5-Rabaptin5 complex also exists in solution, and disruption of this complex by mutation abrogates endosome fusion.
Organizational Affiliation:
Crystallography Research Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, Oklahoma 73104, USA.
