Nuclear Transport of Granzyme B (Fragmentin-2)

摘要: Cytotoxic T and natural killer cells are able to kill their target through synergistic action of the pore-forming protein perforin serine protease granzyme B, resulting in very distinctive nuclear changes typical apoptosis. Whereas acts at membrane, B appears be both capable entering cytoplasm accumulating isolated nuclei. In this study we examine transport fluoresceinated vivo intact presence vitro semi-permeabilized using confocal laser scanning microscopy. Granzyme alone was observed enter but did not accumulate sublytic concentrations perforin, however, it accumulated strongly cell nuclei levels maximally about 1.5 times those after 2.5 h. assays showed maximal nucleolar accumulation 2.5- 3-fold cytoplasm. contrast signal-dependent SV40 large tumor antigen (T-Ag) fusion proteins vitro, nuclear/nucleolar import independent ATP inhibitable by non-hydrolyzable GTP analog GTPgammaS (guanosine 5'-O-(3-thiotriphosphate)). Similar T-Ag proteins, dependent on exogenously added cytosol. Specific inhibitors activity had no effect accumulation, implying that proteolytic essential for targeting. The results imply (32 kDa) may transported from nucleus passive diffusion binding factors a cytosolic factor-mediated process. Active properties were normal unlabeled envelope pore complex substrates.