The small GTPase Rab6a is involved in the regulation of membrane traffic from the Golgi apparatus towards the endoplasmic reticulum (ER) in a coat complex coatomer protein I (COPI)-independent pathway. Here, we used a yeast two-hybrid approach to identify binding partners of Rab6a. In particular, we identified the dynein-dynactin-binding protein Bicaudal-D1 (BICD1), one of the two mammalian homologues of Drosophila Bicaudal-D. BICD1 and BICD2 colocalize with Rab6a on the trans-Golgi network (TGN) and on cytoplasmic vesicles, and associate with Golgi membranes in a Rab6-dependent manner. Overexpression of BICD1 enhances the recruitment of dynein-dynactin to Rab6a-containing vesicles. Conversely, overexpression of the carboxy-terminal domain of BICD, which can interact with Rab6a but not with cytoplasmic dynein, inhibits microtubule minus-end-directed movement of green fluorescent protein (GFP)-Rab6a vesicles and induces an accumulation of Rab6a and COPI-independent ER cargo in peripheral structures. These data suggest that coordinated action between Rab6a, BICD and the dynein-dynactin complex controls COPI-independent Golgi-ER transport.

Animals, Biological Transport/physiology, COS Cells, Coat Protein Complex I/physiology, Coatomer Protein/*physiology, Drosophila Proteins/*physiology, Dyneins/*physiology, Endoplasmic Reticulum/*physiology, Golgi Apparatus/*physiology, Hela Cells, Humans, Microtubule-Associated Proteins/*physiology, Molecular Motor Proteins/physiology, Molecular Sequence Data, rab GTP-Binding Proteins/physiology,
Nature Cell Biology
986-992 + 1 (for illustration)
Erasmus MC: University Medical Center Rotterdam

Matanis, T, Akhmanova, A.S, Wulf, P, del Nery, E, Weide, T, Stepanova, T, … Hoogenraad, C.C. (2002). Bicaudal-D regulates COPI-independent Golgi-ER transport by recruiting the dynein-dynactin motor complex. Nature Cell Biology, 4(12), 986–992. doi:10.1038/ncb891