The BioGRID | PUBLICATION VIEW

	Cell Nov (2002); 111(4):577-88
Forward transport. 14-3-3 binding overcomes retention in endoplasmic reticulum by dibasic signals.
O'Kelly I, Butler MH, Zilberberg N, Goldstein SA
Yale University School of Medicine, Department of Pediatrics, Department of Cellular and Molecular Physiology, Boyer Center for Molecular Medicine, New Haven, CT 06536, USA.
Abstract: Proteins with dibasic retention motifs are subject to retrograde transport to endoplasmic reticulum (ER) by COPI-coated vesicles. As forward transport requires escape from ER retention, general release mechanisms have been expected. Here, KCNK3 potassium channels are shown to bear two cytoplasmic trafficking motifs: an N-terminal dibasic site that binds beta-COP to hold channels in ER and a C-terminal "release" site that binds the ubiquitous intracellular regulator 14-3-3beta on a nonclassical motif in a phosphorylation-dependent fashion to suppress beta-COP binding and allow forward transport. The strategy appears to be common. The major histocompatibility antigen class II-associated invariant chain Iip35 exhibits dibasic retention, carries a release motif, and shows mutually exclusive binding of beta-COP and 14-3-3beta on adjacent N-terminal sites. Other retained proteins are demonstrated to carry functional 14-3-3beta release motifs.
[PUBMED: 12437930]