Early/recycling endosomes-to-TGN transport involves two SNARE complexes and a Rab6 isoform.
The molecular mechanisms underlying early/recycling endosomes-to-TGN transport are still not understood. We identified interactions between the TGN-localized putative t-SNAREs syntaxin 6, syntaxin 16, and Vti1a, and two early/recycling endosomal v-SNAREs, VAMP3/cellubrevin, and VAMP4. Using a novel permeabilized cell system, these proteins were functionally implicated in the post-Golgi retrograde transport step. The function of Rab6a' was also required, whereas its closely related isoform, Rab6a, has previously been implicated in Golgi-to-endoplasmic reticulum transport. Thus, our study shows that membrane exchange between the early endocytic and the biosynthetic/secretory pathways involves specific components of the Rab and SNARE machinery, and suggests that retrograde transport between early/recycling endosomes and the endoplasmic reticulum is critically dependent on the sequential action of two members of the Rab6 subfamily.
Mallard
Frédéric
F
UMR144 Curie/CNRS, Institut Curie, F-75248 Paris Cedex 05, France.
Tang
Bor Luen
BL
Galli
Thierry
T
Tenza
Danièle
D
Saint-Pol
Agnès
A
Yue
Xu
X
Antony
Claude
C
Hong
Wanjin
W
Goud
Bruno
B
Johannes
Ludger
L
D000818:Animals; D001693:Biological Transport, Active; D016466:CHO Cells; D002352:Carrier Proteins / Q000378:metabolism*; D006224:Cricetinae; D011992:Endosomes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050600:SNARE Proteins; D022603:Shiga Toxins / Q000378:metabolism; D051438:Syntaxin 16; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism*
D002352:Carrier Proteins; D008565:Membrane Proteins; D020033:Protein Isoforms; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; C094135:Rab6 protein; D050600:SNARE Proteins; D022603:Shiga Toxins; D051438:Syntaxin 16; C491419:VTI1A protein, human; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins