SORTING BY COP I-COATED VESICLES UNDER INTERPHASE AND MITOTIC CONDITIONS

COP I-coated vesicles were analyzed for their content of resident Golg i enzymes (N-acetylgalactosaminyltransferase; N-acetylglucosaminyltran sferase I; mannosidase II; galactosyltransferase), cargo (rat serum al bumin; polyimmunoglobulin receptor), and recycling proteins (-KDEL rec eptor: ERGIC-53/p58) using biochemical and morphological techniques. T he levels of these proteins were similar when the vesicles were prepar ed under interphase or mitotic conditions Showing that sorting was una ffected. The average density relative to starting membranes for reside nt enzymes (14-30%), cargo (16-23%), and recycling proteins (81-125%) provides clues to the function of COP I vesicles in transport through the Golgi apparatus.