Open AccessRPS3a Over-Expressed in HBV-Associated Hepatocellular Carcinoma Enhances the HBx-Induced NF-κB Signaling via Its Novel Chaperoning Function
Author(s) -
Keo Heun Lim,
Kyun-Hwan Kim,
Seong Il Choi,
Eun Sook Park,
Seung Hwa Park,
Kisun Ryu,
Yong Kwang Park,
So Young Kwon,
Seung Won Yang,
Han Chu Lee,
In Kyung Sung,
Baik Lin Seong
Publication year - 2011
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0022258
Subject(s) - hbx , carcinogenesis , hepatitis b virus , nf κb , hepatocellular carcinoma , biology , signal transduction , cancer research , chemistry , microbiology and biotechnology , virology , virus , genetics , gene
Hepatitis B virus (HBV) infection is one of the major causes of hepatocellular carcinoma (HCC) development. Hepatitis B virus X protein (HBx) is known to play a key role in the development of hepatocellular carcinoma (HCC). Several cellular proteins have been reported to be over-expressed in HBV-associated HCC tissues, but their role in the HBV-mediated oncogenesis remains largely unknown. Here, we explored the effect of the over-expressed cellular protein, a ribosomal protein S3a (RPS3a), on the HBx-induced NF-κB signaling as a critical step for HCC development. The enhancement of HBx-induced NF-κB signaling by RPS3a was investigated by its ability to translocate NF-κB (p65) into the nucleus and the knock-down analysis of RPS3a. Notably, further study revealed that the enhancement of NF-κB by RPS3a is mediated by its novel chaperoning activity toward physiological HBx. The over-expression of RPS3a significantly increased the solubility of highly aggregation-prone HBx. This chaperoning function of RPS3a for HBx is closely correlated with the enhanced NF-κB activity by RPS3a. In addition, the mutational study of RPS3a showed that its N-terminal domain (1–50 amino acids) is important for the chaperoning function and interaction with HBx. The results suggest that RPS3a, via extra-ribosomal chaperoning function for HBx, contributes to virally induced oncogenesis by enhancing HBx-induced NF-κB signaling pathway.