tGolgin-1 (p230, golgin-245) modulates Shiga-toxin transport to the Golgi and Golgi motility towards the microtubule-organizing centre

J Cell Sci. 2005 May 15;118(Pt 10):2279-93. doi: 10.1242/jcs.02358. Epub 2005 May 3.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Autoantigens / biosynthesis
  • Autoantigens / genetics
  • Autoantigens / metabolism*
  • Brefeldin A / pharmacology
  • Endosomes / metabolism
  • Endosomes / ultrastructure
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • HeLa Cells
  • Humans
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Microscopy, Electron, Transmission
  • Microtubule-Organizing Center / metabolism*
  • Microtubule-Organizing Center / ultrastructure
  • Protein Synthesis Inhibitors / pharmacology
  • Protein Transport
  • RNA, Small Interfering / genetics
  • Shiga Toxin / metabolism*

Substances

  • Autoantigens
  • GOLGA4 protein, human
  • Membrane Proteins
  • Protein Synthesis Inhibitors
  • RNA, Small Interfering
  • Brefeldin A
  • Shiga Toxin