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Cargo selection into COPII vesicles is driven by the Sec24p subunit
Author(s) -
Miller Elizabeth,
Antonny Bruno,
Hamamoto Susan,
Schekman Randy
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf605
Subject(s) - copii , copi , vesicle , biology , endoplasmic reticulum , vesicular transport proteins , golgi apparatus , microbiology and biotechnology , clathrin adaptor proteins , protein subunit , cytoplasm , membrane , secretory pathway , biochemistry , vacuole , gene , clathrin , vacuolar protein sorting
Transport of secretory proteins out of the endoplasmic reticulum (ER) is mediated by vesicles generated by the COPII coat complex. In order to understand how cargo molecules are selected by this cytoplasmic coat, we investigated the functional role of the Sec24p homolog, Lst1p. We show that Lst1p can function as a COPII subunit independently of Sec24p on native ER membranes and on synthetic liposomes. However, vesicles generated with Lst1p in the absence of Sec24p are deficient in a distinct subset of cargo molecules, including the SNAREs, Bet1p, Bos1p and Sec22p. Consistent with the absence of any SNAREs, these vesicles are unable to fuse with Golgi membranes. Furthermore, unlike Sec24p, Lst1p fails to bind to Bet1p in vitro , indicating a direct correlation between cargo binding and recruitment into vesicles. Our data suggest that the principle role of Sec24p is to discriminate cargo molecules for incorporation into COPII vesicles.