Signals for COPII-dependent export from the ER: what's the ticket out?
Export of many secretory proteins from the endoplasmic reticulum (ER) relies on signal-mediated sorting into ER-derived transport vesicles. Recent work on the coat protein complex II (COPII) provides new insight into the mechanisms and signals that govern this selective export process. Conserved di-acidic and di-hydrophobic motifs found in specific transmembrane cargo proteins are required for their selection into COPII-coated vesicles. These signaling elements are cytoplasmically exposed and recognized by subunits of the COPII coat. Certain soluble cargo molecules depend on receptor-like proteins for efficient ER export, although signals that direct soluble cargo into ER-derived vesicles are less defined.
Barlowe
Charles
C
Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA. barlowe@dartmouth.edu
D000818:Animals; D022181:COP-Coated Vesicles / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D021381:Protein Transport / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*