clusters
‐coated transport carriers and promotes early secretory pathway organization
Publication
, Journal Article
Johnson, A; Bhattacharya, N; Hanna, M; Pennington, JG; Schuh, AL; Wang, L; Otegui, MS; Stagg, SM; Audhya, A
Published in: The EMBO Journal
In mammalian cells, cargo‐laden secretory vesicles leave the endoplasmic reticulum (
) en route to
‐Golgi intermediate compartments (
) in a manner dependent on the
coat complex. We report here that
‐coated transport carriers traverse a submicron,
(Trk‐fused gene)‐enriched zone at the
/
interface. The architecture of
complexes as determined by three‐dimensional electron microscopy reveals the formation of flexible, octameric cup‐like structures, which are able to self‐associate to generate larger polymers
. In cells, loss of
function dramatically slows protein export from the
and results in the accumulation of
‐coated carriers throughout the cytoplasm. Additionally, the tight association between
and
membranes is lost in the absence of
. We propose that
functions at the
/
interface to locally concentrate
‐coated transport carriers and link exit sites on the
to
membranes. Our findings provide a new mechanism by which
‐coated carriers are retained near their site of formation to facilitate rapid fusion with neighboring
membranes upon uncoating, thereby promoting interorganellar cargo transport.
