A role for the Rab6B Bicaudal-D1 interaction in retrograde transport in neuronal cells.
The Rab6 subfamily of small GTPases consists of three different isoforms: Rab6A, Rab6A' and Rab6B. Both Rab6A and Rab6A' are ubiquitously expressed whereas Rab6B is predominantly expressed in brain. Recent studies have shown that Rab6A' is the isoform regulating the retrograde transport from late endosomes via the Golgi to the ER and in the transition from anaphase to metaphase during mitosis. Since the role of Rab6B is still ill defined, we set out to characterize its intracellular environment and dynamic behavior. In a Y-2H search for novel Rab6 interacting proteins, we identified Bicaudal-D1, a large coiled-coil protein known to bind to the dynein/dynactin complex and previously shown to be a binding partner for Rab6A/Rab6A'. Co-immunoprecipitation studies and pull down assays confirmed that Bicaudal-D1 also interacts with Rab6B in its active form. Using confocal laser scanning microscopy it was established that Rab6B and Bicaudal-D1 co-localize at the Golgi and vesicles that align along microtubules. Furthermore, both proteins co-localized with dynein in neurites of SK-N-SH cells. Live cell imaging revealed bi-directional movement of EGFP-Rab6B structures in SK-N-SH neurites. We conclude from our data that the brain-specific Rab6B via Bicaudal-D1 is linked to the dynein/dynactin complex, suggesting a regulatory role for Rab6B in the retrograde transport of cargo in neuronal cells.
Wanschers
Bas F J
BF
Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences (NCMLS), Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 28, 6525 GA, Nijmegen, The Netherlands.
van de Vorstenbosch
Rinske
R
Schlager
Max A
MA
Splinter
Daniël
D
Akhmanova
Anna
A
Hoogenraad
Casper C
CC
Wieringa
Bé
B
Fransen
Jack A M
JA
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C109571:BICD1 protein, human; D003598:Cytoskeletal Proteins; D020033:Protein Isoforms; C094135:Rab6 protein; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D020691:rab GTP-Binding Proteins