Through induction of juxtaposition and tyrosine kinase activity of Jak1, X-gene product of hepatitis B virus stimulates Ras and the transcriptional activation through AP-1, NF-kappa B, and SRE enhancers
Ht. Kim et al., Through induction of juxtaposition and tyrosine kinase activity of Jak1, X-gene product of hepatitis B virus stimulates Ras and the transcriptional activation through AP-1, NF-kappa B, and SRE enhancers, BIOC BIOP R, 286(5), 2001, pp. 886-894
Citations number
30
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Here, based on the recent finding of HBx (X-gene product of hepatitis B vir
us) as the inducer of Jak1, we investigated the mechanism for the HBx-media
ted host cell regulation and found that (i) HBx associates specifically wit
h Jak1 in vivo, (ii) HBx itself forms a dimer which leads to juxtaposition
of associated Jak1 and subsequent activation of the tyrosine kinase activit
y of Jakl; (iii) HBx-mediated activation of the promoters containing AP-1-,
NF-kappaB-, SRE-, and SIE-sites is dependent on the activation of Jak1; (i
v) Jak1, once activated by HBx, induces Ras activity through recruitment of
Grb2 and induces tyrosine phosphorylation of Raft, but not shc. These find
ings show that previously reported functions of HBx, such as activation of
multiple signaling pathways and transcriptional activation are attributable
to HBx-mediated Jak1 activation. (C) 2001 Academic Press.