Early/Recycling Endosomes-to-TGN Transport Involves Two SNARE Complexes and a Rab6 Isoform

• Published in: The Journal of cell biology 2002-02, Vol.156 (4), p.653-664
• Main Authors: Mallard, Frédéric, Tang, Bor Luen, Galli, Thierry, Tenza, Danièle, Saint-Pol, Agnès, Yue, Xu, Antony, Claude, Hong, Wanjin, Goud, Bruno, Johannes, Ludger
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Biological Transport, Active; Carrier Proteins - metabolism; Cells; Cellular biology; CHO Cells; Cricetinae; Cytosol; Endosomes; Endosomes - metabolism; Epithelial cells; HeLa Cells; Humans; Membrane Proteins - metabolism; Membranes; Protein Isoforms - metabolism; Proteins; Qa-SNARE Proteins; Qb-SNARE Proteins; rab GTP-Binding Proteins - metabolism; Receptors; Shiga Toxins - metabolism; SNARE Proteins; Sulfation; Syntaxin 16; trans-Golgi Network - metabolism; Vesicle-Associated Membrane Protein 3; Vesicular Transport Proteins
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200110081

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.