Chakrabarti, RanjanJoly, MargueriteCorvera, Silvia2022-08-232022-08-231993-10-012008-10-31J Cell Biol. 1993 Oct;123(1):79-87.0021-9525 (Print)8408208https://hdl.handle.net/20.500.14038/42625Mechanisms for intracellular retention of proteins are induced during adipocytic differentiation of 3T3-L1 cells. To investigate the potential role of clathrin lattices in these retention processes, we performed a morphological and biochemical analysis of coated vesicle components in 3T3-L1 cells. Optical sectioning and image restoration revealed a marked increase in the staining of clathrin and beta adaptins in the perinuclear region of cells with differentiation. In addition, predominance of beta (subunit of the AP-2, plasma membrane adaptor) over beta' (subunit of the AP-1, Golgi adaptor) adaptin was observed in immunoblots of clathrin-coated vesicles purified from nondifferentiated fibroblasts, and this ratio was reversed in coated vesicles purified from differentiated adipocytes. These results indicate that the relative abundance of TGN-derived clathrin lattices increases markedly during adipocytic differentiation. Subcellular fractionation indicated that cytosolic AP-1 and AP-2 adaptors comprised approximately 70% of the total cellular adaptor pool. Interestingly, neither the concentration nor the relative ratio of cytosolic AP-1 to AP-2 adaptors increased significantly during differentiation. These data suggest that the increase in TGN-derived lattices results from differentiation-induced mechanisms for enhanced assembly or stabilization of adaptors on Golgi membranes. Interestingly, double-immunofluorescence microscopy also revealed that whereas extensive colocalization between clathrin and beta adaptins occurred both in fibroblasts and adipocytes, structures stained only with anti-adaptin antibody could be detected. Taken together these results suggest that membranes coated with adaptors, but not clathrin, can exist in these cells.en-US3T3 CellsAdaptor Protein Complex alpha SubunitsAdaptor Protein Complex gamma SubunitsAdaptor Proteins, Vesicular TransportAdipocytesAnimalsCell Compartmentation*Cell Differentiation*ClathrinCoated Pits, Cell-MembraneCytosolFibroblastsFluorescent Antibody TechniqueGolgi ApparatusIntracellular MembranesMiceProteinsSubcellular FractionsCell BiologyMolecular BiologyJournal Articlehttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=1955&context=oapubs&unstamped=1https://escholarship.umassmed.edu/oapubs/956659137oapubs/956