Cell Biology

Making an Early Exit

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Science  09 Feb 2001:
Vol. 291, Issue 5506, pp. 949
DOI: 10.1126/science.291.5506.949A

Newly synthesized integral membrane and secretory proteins must traverse the endoplasmic reticulum (ER) and then the Golgi complex en route to the cell surface. Transport from the ER to the Golgi complex has been the subject of much scrutiny. Muñiz et al. have used a cell free system that reconstitutes budding from the ER of yeast cells to examine the export of proteins that, lacking a transmembrane anchor, are linked by a glycolipid (GPI) to the membrane. Such GPI-anchored proteins were found to leave the ER in vesicles distinct from those used by integral membrane proteins. The sorting and packaging mechanism that recognizes this class of proteins remains unidentified, but these findings require some adjustment to the idea that all proteins leave the ER together to be sorted later in the pathway. — SMH

Cell104, 313 (2001).


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