A role for kinesin-2 in COPI-dependent recycling between the ER and the Golgi complex.
Transport carriers operating between early compartments in the mammalian secretory pathway have to travel long distances in the cell by mostly relying on the microtubule network and its associated motor proteins. Although anterograde transport from the endoplasmic reticulum (ER) to the Golgi complex is mediated by cytoplasmic dynein, the identity of the motor(s) mediating transport in the retrograde direction is presently unclear. Some studies have suggested that the heterotrimeric kinesin-2 complex plays a role in transport between the ER and the Golgi. Here, we have examined kinesin-2 function by using an RNA-interference approach to downregulate the expression of KAP3, the nonmotor subunit of kinesin-2, in HeLa cells. KAP3 silencing results in the fragmentation of the Golgi apparatus and a change in the steady-state localization of the KDEL-receptor (KDEL-R). Using specific transport assays, we show that the rate of anterograde secretory traffic is unaffected in these cells but that KDEL-R-dependent retrograde transport is strongly abrogated. Our data strongly support a role for kinesin-2 in the KDEL-R-/COPI-dependent retrograde transport pathway from the Golgi complex to the ER.
Stauber
Tobias
T
Cell Biology and Biophysics Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Simpson
Jeremy C
JC
Pepperkok
Rainer
R
Vernos
Isabelle
I
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D015153:Blotting, Western; D020755:Coat Protein Complex I / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005786:Gene Expression Regulation; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D034622:RNA Interference; D018000:Receptors, Peptide / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D020755:Coat Protein Complex I; D003598:Cytoskeletal Proteins; D017931:DNA Primers; C489304:KDELR1 protein, human; C509805:KIF2A protein, human; C484407:KIFAP3 protein, human; D018000:Receptors, Peptide; D016547:Kinesins