The HCV core protein interacts with PA28 under living cell conditions

The HCV core protein interacts with PA28 under living cell conditions. Since the nuclear localization of PA28 is dependent on a c Myc like NLS, deletion of the NLS in PA28 should shift its localization into the cytoplasm. When PA28 was fused to the C terminus of the red uorescence protein,and coexpressed with purchase Dapagliflozin EGFP Core151 in HeLa cells, EGFP Core151 colocalized with DsRed PA28 in the nucleus, In the presence of DsRed PA28 lacking the NLS, however, EGFP Core151 was predominantly detected in the cytoplasm and was colocalized with DsRed PA28 NLS, The detection of EGFP Core151 in the nucleus of cells over expressing DsRed PA28 NLS was probably due to the inter action of the core protein with endogenous PA28 in the nucleus. The cytoplasmic localization of EGFP Core151 Infectious causes of cancer was also detected with DsRed PA28 NLS in 293T cells, These data indicate that the HCV core protein binds to PA28 in living cells. DEN and JEV are both members of the Flaviviridae family, which also includes HCV, The HCV core protein shares 22 and 30% homology with the DEN and JEV core proteins within the N terminal 50 amino acids, respectively. Also similar to HCV, the core proteins of DEN and JEV are basic. The EGFP fused JEV core protein lacking the C termi nal hydrophobic region can be visualized in both the cytoplasm and nucleus, The intracellular localization of EGFP JEV C was quite distinct from that of DsRed PA28, and coexpression with DsRed PA28 NLS did not affect the subcellular localization of the protein, Similar results were obtained by coexpression of the EGFP fused DEN core protein lacking the C terminal hydrophobic region, EGFP DEN C was not colocalized with DsRed PA28 and was not affected by expression of DsRed PA28 NLS, Endogenous PA28 was coprecipitated with EGFP Core151 by anti GFP antibody but not with EGFP DEN C or EGFP JEV C, These data suggest that PA28 spe cically interacts with the HCV core protein but not with DEN and JEV core proteins in living cells. Mapping of the PA28 binding region of the HCV core protein. To determine the region of the HCV core protein responsible for PA28 binding, the interactions of PA28 with deletion mutants of the HCV core protein were examined. When Flag Core mutants were expressed in 293T cells, endogenous PA28 was coimmunoprecipitated with purchase SMER3 Flag Core191, Flag Core24 191, and Flag Core38 191 by anti Flag antibody but not with Flag Core72 191 and Flag Core92 191,the levels of protein expression were the same for all constructs, Conversely, Flag Core191, Flag Core24 191, and Flag Core38 191, but not Flag Core72 191 and Flag Core92 191, were coprecipitated with endogenous PA28 by anti PA28 antibody. These results indicate that the N terminal 37 amino acids of the HCV core protein are not involved in the interaction with PA28.