title: The trials and tubule-ations of Rab6 involvement in Golgi-to-ER retrograde transport.
abstract: In the early secretory pathway, membrane flow in the anterograde direction from the endoplasmic reticulum (ER) to the Golgi complex needs to be tightly co-ordinated with retrograde flow to maintain the size, composition and functionality of these two organelles. At least two mechanisms of transport move material in the retrograde direction: one regulated by the cytoplasmic coatomer protein I complex (COPI), and a second COPI-independent pathway utilizing the small GTP-binding protein Rab6. Although the COPI-independent pathway was discovered 15 years ago, it remains relatively poorly characterized, with only a handful of machinery molecules associated with its operation. One feature that makes this pathway somewhat unusual, and potentially difficult to study, is that the transport carriers predominantly seem to be tubular rather than vesicular in nature. This suggests that the regulatory machinery is likely to be different from that associated with vesicular transport pathways controlled by conventional coat complexes. In the present mini-review, we have highlighted the key experiments that have characterized this transport pathway so far and also have discussed the challenges that lie ahead with respect to its further characterization.
authors.affiliation: *School of Biology and Environmental Science & Conway Institute of Biomolecular and Biomedical Research, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
authors.forename: Linda F
authors.initials: LF
authors.lastname: Heffernan
authors.affiliation: *School of Biology and Environmental Science & Conway Institute of Biomolecular and Biomedical Research, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Simpson
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001692:Biological Transport; D020755:Coat Protein Complex I / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D006056:Golgi Apparatus / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D053141:Organelle Size; D021381:Protein Transport; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D020755:Coat Protein Complex I; D007527:Isoenzymes; C094135:Rab6 protein; D020691:rab GTP-Binding Proteins