Rab6 family proteins interact with the dynein light chain protein DYNLRB1.
The small GTPase Rab6 is a key regulator in the retrograde transfer from endosomes via the Golgi to the ER. Three isoforms of Rab6 have been identified, the ubiquitously expressed Rab6A and Rab6A', and the brain specific Rab6B. Recent studies have shown that Rab6A' is the major isoform regulating this retrograde transport. Cytoplasmic dynein is the main motor protein complex for this transport. Dynein consists of two heavy chains, two intermediate chains, four light intermediate chains and several light chains, called roadblock/LC7 proteins or DYNLRB proteins. In mammalian cells two light chain isoforms have been identified, DYNLRB1 and DYNLRB2. We here show with yeast-two-hybrid, co-immunoprecipitation and pull down studies that DYNLRB1 specifically interacts with all three Rab6 isoforms and co-localises at the Golgi. This is the first example of a direct interaction between Rab6 isoforms and the dynein complex. Pull down experiments showed further preferred association of DYNLRB1 with GTP-bound Rab6A and interestingly GDP-bound Rab6A' and Rab6B. In addition DYNLRB1 was found in the Golgi apparatus where it co-localises with EYFP-Rab6 isoforms. DYNLRB is a putative modulator of the intrinsic GTPase activity of GTP-binding proteins. In vitro we were not able to reproduce this effect on Rab6 GTPase activity.
Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Bas
B
Wanschers
Rinske
R
van de Vorstenbosch
Mietske
M
Wijers
Bé
B
Wieringa
Stephen M
SM
King
Jack
J
Fransen
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D056445:Cytoplasmic Dyneins; D004398:Dyneins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006056:Golgi Apparatus / Q000648:ultrastructure; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*
C504797:DYNLRB1 protein, human; D020033:Protein Isoforms; C094135:Rab6 protein; D011993:Recombinant Fusion Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D056445:Cytoplasmic Dyneins; D004398:Dyneins; D020691:rab GTP-Binding Proteins