Interaction of filipin with junctional membrane at different stages of the junction's life history.
The relationship of filipin-sterol complexes to tight and gap junctions during their formation, maturation, internalization, and degradation was studied in separate cell lines. Filipin-sterol complexes tended to be excluded from mature junctions in tight junction forming COLO 316 cells and gap junction forming SW-13 cells. Once internalized, unlabeled junctional membrane appeared to fuse with heavily labeled vesicles, presumably lysosomes. Although the absence of filipin-sterol complexes from junctional membrane does not necessarily reflect the absolute sterol content of this membrane, the fact that filipin-sterol complexes are largely excluded from these areas indicates that this membrane is different from surrounding membrane. The absence of filipin-sterol complexes also permits the visualization of 'mixing' of this specialized unlabeled membrane domain with other filipin labeled membrane systems.
D000310:Adrenal Gland Neoplasms; D002460:Cell Line; D002462:Cell Membrane / Q000032:analysis; D003034:Coated Pits, Cell-Membrane / Q000032:analysis; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D005372:Filipin; D006801:Humans; D007365:Intercellular Junctions / Q000032:analysis* / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000032:analysis; D008247:Lysosomes / Q000648:ultrastructure; D008561:Membrane Fusion; D008854:Microscopy, Electron; D009940:Organoids / Q000648:ultrastructure; D010051:Ovarian Neoplasms; D013261:Sterols / Q000032:analysis*
D013261:Sterols; D005372:Filipin