Cargo Capture and Bulk Flow in the Early Secretory Pathway.
Transport of newly synthesized proteins from the endoplasmic reticulum (ER) to the Golgi complex is highly selective. As a general rule, such transport is limited to soluble and membrane-associated secretory proteins that have reached properly folded and assembled conformations. To secure the efficiency, fidelity, and control of this crucial transport step, cells use a combination of mechanisms. The mechanisms are based on selective retention of proteins in the ER to prevent uptake into transport vesicles, on selective capture of proteins in COPII carrier vesicles, on inclusion of proteins in these vesicles by default as part of fluid and membrane bulk flow, and on selective retrieval of proteins from post-ER compartments by retrograde vesicle transport.
Biochemistry Department, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755; email: Charles.Barlowe@Dartmouth.edu.
Charles
C
Barlowe
Institute of Biochemistry, ETH Zurich, Zurich CH-8093, Switzerland.
Ari
A
Helenius
D000818:Animals; D022181:COP-Coated Vesicles / Q000378:metabolism; D060746:Endoplasmic Reticulum-Associated Degradation; D006801:Humans; D021381:Protein Transport; D055571:Secretory Pathway; D022161:Transport Vesicles / Q000378:metabolism
ER; Golgi; coat proteins; protein secretion; trafficking