Annexin VI-mediated Loss of Spectrin during Coated Pit Budding Is Coupled to Delivery of LDL to Lysosomes

摘要: Previously we reported that annexin VI is required for the budding of clathrin-coated pits from human fibroblast plasma membranes in vitro. Here show bound to NH2-terminal 28-kD portion membrane spectrin as effective cytosolic supporting coated pit budding. Annexin VI-dependent accompanied by loss approximately 50% and blocked cysteine protease inhibitor N-acetyl-leucyl-leucyl-norleucinal (ALLN). Incubation fibroblasts presence ALLN initially blocks uptake low density lipoprotein (LDL), but cells recover after 1 h internalize LDL with normal kinetics. The internalized under these conditions, however, fails migrate center cell not degraded. ALLN-treated have twice many twofold more clathrin, suggesting new assembled. does inhibit. Finally, microinjection a truncated inhibits vitro has same effect on internalization ALLN. These findings suggest are able make at least two types pits, one which requires activation disconnect clathrin lattice cytoskeleton during final stages