2014/09/16 by Vassilis Bitsikas, Ivan R. Corrêa, Benjamin J. Nichols · 2 citations
Biochemistry, Genetics and Molecular Biology · #Cellular transport and secretion #Caveolin-1 and cellular processes #Glycosylation and Glycoproteins Research
paper · pdf · doi:10.7554/elife.03970
openalex publication_date 2014/09/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Several different endocytic pathways have been proposed to function in mammalian cells. Clathrin-coated pits are well defined, but the identity, mechanism and function of alternative pathways have been controversial. Here we apply universal chemical labelling of plasma membrane proteins to define all primary endocytic vesicles, and labelling of specific proteins with a reducible SNAP-tag substrate. These approaches provide high temporal resolution and stringent discrimination between surface-connected and intracellular membranes. We find that at least 95% of the earliest detectable endocytic vesicles arise from clathrin-coated pits. GPI-anchored proteins, candidate cargoes for alternate pathways, are also found to enter the cell predominantly via coated pits. Experiments employing a mutated clathrin adaptor reveal distinct mechanisms for sorting into coated pits, and thereby explain differential effects on the uptake of transferrin and GPI-anchored proteins. These data call for a revision of models for the activity and diversity of endocytic pathways in mammalian cells.