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De novo formation, fusion and fission of mammalian COPII‐coated endoplasmic reticulum exit sites
Author(s) -
Stephens David J
Publication year - 2003
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.embor736
Subject(s) - copii , endoplasmic reticulum , copi , golgi apparatus , microbiology and biotechnology , vesicular transport proteins , secretory pathway , biology , cytoplasm , vacuole , vacuolar protein sorting
Transport between the endoplasmic reticulum (ER) and Golgi is mediated by the sequential action of the COPII and COPI coat complexes. COPII subunits are recruited to the ER membrane where they mediate the selection of cargo for transport to the Golgi, and also membrane deformation and vesicle formation. New ER exit sites can be generated by lateral growth and medial fission (in Pythium sp.) or by de novo formation (in Pichia pastoris ) but it is not known how mammalian ER exit sites form. Here, time‐lapse imaging of COPII‐coated structures in live mammalian cells reveals that the number of ER export sites increases greatly during interphase by de novo formation. These results show the fusion of pre‐existing ER export sites and the fission of larger structures. These three mechanisms of de novo formation, fusion and fission probably cooperate to regulate the size of these sites in mammalian cells.