Evidence for the lipidic nature of tight junction strands

摘要: We examine here the proposition that membrane lipids1–4, rather than intrinsic proteins5–7, are principal structural elements of strands comprising tight junctions. Our evidence, which is based on direct rapid freezing newly formed junctions between rat prostate epithelial cells, indicates individual junction pairs inverted cylindrical micelles sandwiched linear fusions external leaflets adjacent cells. Although appear as continuous cylinders when fractured near frozen surface, where ice crystals have not damaged plasma membrane, they rows particles deeper in tissue. now interpret these remnants intramembrane disrupted during The morphology and dimensions intact correspond to those lipids hexagonal II phase8,9 this suggests formation requires a phase transition planar lipid bilayer similar invoked models fusion10,11. morphological interpretation explains known functional properties