Anterograde flow of cargo across the Golgi stack potentially mediated via bidirectional “percolating” COPI vesicles
AUTOR(ES)
Orci, Lelio
FONTE
The National Academy of Sciences
RESUMO
How do secretory proteins and other cargo targeted to post-Golgi locations traverse the Golgi stack? We report immunoelectron microscopy experiments establishing that a Golgi-restricted SNARE, GOS 28, is present in the same population of COPI vesicles as anterograde cargo marked by vesicular stomatitis virus glycoprotein, but is excluded from the COPI vesicles containing retrograde-targeted cargo (marked by KDEL receptor). We also report that GOS 28 and its partnering t-SNARE heavy chain, syntaxin 5, reside together in every cisterna of the stack. Taken together, these data raise the possibility that the anterograde cargo-laden COPI vesicles, retained locally by means of tethers, are inherently capable of fusing with neighboring cisternae on either side. If so, quanta of exported proteins would transit the stack in GOS 28–COPI vesicles via a bidirectional random walk, entering at the cis face and leaving at the trans face and percolating up and down the stack in between. Percolating vesicles carrying both post-Golgi cargo and Golgi residents up and down the stack would reconcile disparate observations on Golgi transport in cells and in cell-free systems.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=27036Documentos Relacionados
- Vesicles on strings: Morphological evidence for processive transport within the Golgi stack
- The Golgi-associated COPI-coated buds and vesicles contain β/γ-actin
- Osmotically Induced Cell Volume Changes Alter Anterograde and Retrograde Transport, Golgi Structure, and COPI Dissociation
- Golgi Enzymes Are Enriched in Perforated Zones of Golgi Cisternae but Are Depleted in COPI Vesicles
- The ArfGAP Glo3 Is Required for the Generation of COPI Vesicles
