title: tGolgin-1 (p230, golgin-245) modulates Shiga-toxin transport to the Golgi and Golgi motility towards the microtubule-organizing centre.
abstract: tGolgin-1 (trans-Golgi p230, golgin-245) is a member of a family of large peripheral membrane proteins that associate with the trans-Golgi network (TGN) via a C-terminal GRIP domain. Some GRIP-domain proteins have been implicated in endosome-to-TGN transport but no function for tGolgin-1 has been described. Here, we show that tGolgin-1 production is required for efficient retrograde distribution of Shiga toxin from endosomes to the Golgi. Surprisingly, we also found an indirect requirement for tGolgin-1 in Golgi positioning. In HeLa cells depleted of tGolgin-1, the normally centralized Golgi and TGN membranes were displaced to the periphery, forming 'mini stacks'. These stacks resembled those in cells with disrupted microtubules or dynein-dynactin motor, in that they localized to endoplasmic-reticulum exit sites, maintained their secretory capacity and cis-trans polarity, and were relatively immobile by video microscopy. The mini stacks formed concomitant with a failure of pre-Golgi elements to migrate along microtubules towards the microtubule-organizing centre. The requirement for tGolgin-1 in Golgi positioning did not appear to reflect direct binding of tGolgin-1 to motile pre-Golgi membranes, because distinct Golgi and tGolgin-1-containing TGN elements that formed after recovery of HeLa cells from brefeldin-A treatment moved independently toward the microtubule-organizing centre. These data demonstrate that tGolgin-1 functions in Golgi positioning indirectly, probably by regulating retrograde movement of cargo required for recruitment or activation of dynein-dynactin complexes on newly formed Golgi elements.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6082, USA.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Yoshino
authors.forename: Subba Rao Gangi
authors.initials: SR
authors.lastname: Setty
authors.forename: Clare
authors.initials: C
authors.lastname: Poynton
authors.forename: Eileen L
authors.initials: EL
authors.lastname: Whiteman
authors.forename: Agnès
authors.initials: A
authors.lastname: Saint-Pol
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Burd
authors.forename: Ludger
authors.initials: L
authors.lastname: Johannes
authors.forename: Erika L
authors.initials: EL
authors.lastname: Holzbaur
authors.forename: Michael
authors.initials: M
authors.lastname: Koval
authors.forename: J Michael
authors.initials: JM
authors.lastname: McCaffery
authors.forename: Michael S
authors.initials: MS
authors.lastname: Marks
mesh_terms: D001324:Autoantigens / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D020126:Brefeldin A / Q000494:pharmacology; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D022101:Microtubule-Organizing Center / Q000378:metabolism* / Q000648:ultrastructure; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000235:genetics; D022621:Shiga Toxin / Q000378:metabolism*
chemical_list: D001324:Autoantigens; C098772:GOLGA4 protein, human; D008565:Membrane Proteins; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; D020126:Brefeldin A; D022621:Shiga Toxin