The interaction between hepatitis B virus X protein and AIB1 oncogene is required for the activation of NFκB signal transduction

We identified the interaction between HBV X (HBx) protein and the oncogene AIB1 (amplified in breast cancer 1). A serine/proline motif (SSPSPS) in HBx was found to be required for the interaction. Two LXD motifs [LLXX(X)L, X means any amino acids], LLRNSL and LLDQLHTLL in AIB1 were also found to be involved in the HBx–AIB1 interaction. The HBx–AIB1 interaction was important for the activation of NFκB signal transduction, the HBx mutant that did not interact with AIB1showed dramatically lower NFκB activation activity than the WT HBx. These findings contribute to the new understanding on signal transduction activation mechanisms of HBx.

► Identified that hepatitis B virus X protein interacts with human oncogene AIB1.
► Found HBx–AIB1 interaction important for the activation of NFκB pathway.
► Identified single amino acids in HBx and AIB1 important for the interaction and NFkB activation.
► Found that HBx expressed more in cancerous tissue than non-cancerous tissue from the same liver.