Hepatitis C virus NS3 protein interacts with ELKS-{delta} and ELKS-{alpha}, members of a novel protein family involved in intracellular transport and secretory pathways.
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-delta, 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-delta and its splice variant, ELKS-alpha, 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-delta 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-delta. 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-delta and ELKS-alpha, which may facilitate the virus life cycle and/or mediate the pathogenesis of HCV.
Hidajat
Rachmat
R
Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Nagano-Fujii
Motoko
M
Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Deng
Lin
L
Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Tanaka
Motofumi
M
Division of Gastroenterological Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.|Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Takigawa
Yuki
Y
Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Kitazawa
Sohei
S
Division of Molecular Pathology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Hotta
Hak
H
Division of Microbiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000595:Amino Acid Sequence; D001692:Biological Transport; D045744:Cell Line, Tumor; D018076:DNA, Complementary; D016174:Hepacivirus / Q000502:physiology; D006526:Hepatitis C / Q000378:metabolism / Q000821:virology; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012093:Replicon; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D048868:Adaptor Proteins, Signal Transducing; D000469:Alkaline Phosphatase; D018076:DNA, Complementary; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C468925:ERC1 protein, human; C084422:NS3 protein, hepatitis C virus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases