endocytic pathway

As the exocytic pathway, the endocytic pathway is based on elaborate system of vesiculo-tubular transport (vesicular transport or vesicle transport).

Vesicle transport

Proteins and lipids to be transported are sorted to specific sites on the donor membrane, or compartment, and transport vesicles bud with the aid of cytosolic complexes of coat proteins. Vesicles move along cytoskeletal tracks, either microtubules or actin filaments, with the help of motor proteins. The vesicle is tethered and docked near the target membrane and subsequently fuses with the acceptor bilayer, releasing its contents into the target, or acceptor, compartment.

Vesicular coat proteins mediate the formation of nascent vesicles and select the cargo to be incorporated therein.

As additional coat proteins are discovered that regulate vesicular traffic along very specific intracellular pathways, the possibility looms of regulating the intracellular trafficking and targeting of therapeutic agents by modulation of the action of vesicular coat proteins.

Examples are provided of coat proteins thought to regulate the trafficking of pharmaceutically relevant molecules via clathrin-mediated endocytosis, caveolae-mediated endocytosis, and transcytosis.

Members

 COPI
 COPII
 clathrin

See also

 vesicular transport

References

 Olkkonen VM, Ikonen E. Genetic defects of intracellular-membrane transport. N Engl J Med. 2000 Oct 12;343(15):1095-104. PMID: 11027745

 Gruenberg J, Maxfield FR. Membrane transport in the endocytic pathway. Curr Opin Cell Biol 1995;7:552-563

 Mellman I. Endocytosis and molecular sorting. Annu Rev Cell Dev Biol 1996;12:575-625.