RT Journal Article SR Electronic(1) A1 Hidajat, Rachmat A1 Nagano-Fujii, Motoko A1 Deng, Lin A1 Tanaka, Motofumi A1 Takigawa, Yuki A1 Kitazawa, Sohei A1 Hotta, HakYR 2005 T1 Hepatitis C virus NS3 protein interacts with ELKS-δ and ELKS-α, members of a novel protein family involved in intracellular transport and secretory pathways JF Journal of General Virology, VO 86 IS 8 SP 2197 OP 2208 DO https://doi.org/10.1099/vir.0.80862-0 PB Microbiology Society, SN 1465-2099, AB The NS3 protein of hepatitis C virus (HCV) has a serine protease activity in its N-terminal region, which plays a crucial role in virus replication. This region has also been reported to interact not only with its viral cofactor NS4A, but also with a number of host-cell proteins, which suggests a multifunctional feature of NS3. By means of yeast two-hybrid screening using an N-terminal region of NS3 as bait, a human cDNA encoding a region of ELKS-δ, a member of a novel family of proteins involved in intracellular transport and secretory pathways, was molecularly cloned. Using co-immunoprecipitation, GST pull-down and confocal and immunoelectron microscopic analyses, it was shown that full-length NS3 interacted physically with full-length ELKS-δ and its splice variant, ELKS-α, both in the absence and presence of NS4A, in cultured human cells, including Huh-7 cells harbouring an HCV subgenomic RNA replicon. The degree of binding to ELKS-δ varied with different sequences of the N-terminal 180 residues of NS3. Interestingly, NS3, either full-length or N-terminal fragments, enhanced secretion of secreted alkaline phosphatase (SEAP) from the cells, and the increase in SEAP secretion correlated well with the degree of binding between NS3 and ELKS-δ. Taken together, these results suggest the possibility that NS3 plays a role in modulating host-cell functions such as intracellular transport and secretion through its binding to ELKS-δ and ELKS-α, which may facilitate the virus life cycle and/or mediate the pathogenesis of HCV., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.80862-0