Rab11-FIP2 functions in transferrin recycling and associates with endosomal membranes via its COOH-terminal domain.
Rab11-FIP2 is a recently described member of the Rip11/Rab11-FIP/Rab coupling protein family of Rab11 interacting proteins. Rab11-FIP2 interacts with both Rab11 and myosin Vb and co-localizes with Rab11 in both HeLa and Madin-Darby canine kidney cells (Hales, C. M., Griner, R., Hobdy-Henderson, K. C., Dorn, M. C., Hardy, D., Kumar, R., Navarre, J., Chan, E. K., Lapierre, L. A., and Goldenring, J. R. (2001) J. Biol. Chem. 276, 39067-390751). Here, we characterized the specificity of the interaction between Rab11-FIP2 and Rab11 and report that it does not interact with Rab4, Rab3, Rab5, Rab6, or Rab7. We demonstrate that the COOH-terminal region of Rab11-FIP2, which contains the Rab11 binding domain (RBD), is necessary and sufficient for its early endosomal membrane association. In contrast, the amino-terminal region, which contains a phospholipid binding C2-domain, by itself was insufficient for membrane binding. Expression of a deletion mutant of Rab11-FIP2, containing the RBD, caused tubulation of a transferrin receptor-positive early endosomal compartment in HeLa cells. Endogenous Rab11 was also associated with this compartment. This phenotype cannot be reversed by excess wild-type Rab11, or dominant-positive Rab11 (Rab11Q70L), suggesting that Rab11-FIP2 functions downstream of Rab11 in endosomal trafficking.
Lindsay
Andrew J
AJ
Cell and Molecular Biology Laboratory, Department of Biochemistry, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland.
McCaffrey
Mary W
MW
D000595:Amino Acid Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry* / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010641:Phenotype; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014168:Transferrin / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
D002352:Carrier Proteins; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D014168:Transferrin; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C463963:RAB11FIP2 protein, human