TY - JOUR
T1 - Interaction of hepatitis B viral oncoprotein with cellular target HBXIP dysregulates centrosome dynamics and mitotic spindle formation
AU - Wen, Yunfei
AU - Golubkov, Vladislav S.
AU - Strongin, Alex Y.
AU - Jiang, Wei
AU - Reed, John C.
PY - 2008/2/1
Y1 - 2008/2/1
N2 - Hepatitis B virus infection is associated with hepatocellular carcinoma, claiming 1 million lives annually worldwide. To understand the carcinogenic mechanism of hepatitis B virus-encoded oncoprotein HBx, we explored the function of HBx interaction with its cellular target HBXIP. Previously, we demonstrated that viral HBx and cellular HBXIP control mitotic spindle formation, regulating centrosome splitting. By using various fragments of HBx, we determined that residues 137CRHK140 within HBx are necessary for binding HBXIP. Mutation of the 137CRHK140 motif in HBx abolished its ability to bind HBXIP and to dysregulate centrosome dynamics in HeLa and immortal diploid RPE-1 cells. Unlike wild-type HBx, which targets to centrosomes as determined by subcellular fractionation and immunofluorescence microscopy, HBx mutants failed to localize to centrosomes. Overexpression of viral HBx wildtype protein and knockdown of endogenous HBXIP altered centrosome assembly and induced modifications of pericentrin and centrin-2, two essential proteins required for centrosome formation and function, whereas HBXIP nonbinding mutants of HBx did not. Overexpression of HBXIP or fragments of HBXIP that bind HBx neutralized the effects of viral HBx on centrosome dynamics and spindle formation. These results suggest that HBXIP is a critical target of viral HBx for promoting genetic instability through formation of defective spindles and subsequent aberrant chromosome segregation.
AB - Hepatitis B virus infection is associated with hepatocellular carcinoma, claiming 1 million lives annually worldwide. To understand the carcinogenic mechanism of hepatitis B virus-encoded oncoprotein HBx, we explored the function of HBx interaction with its cellular target HBXIP. Previously, we demonstrated that viral HBx and cellular HBXIP control mitotic spindle formation, regulating centrosome splitting. By using various fragments of HBx, we determined that residues 137CRHK140 within HBx are necessary for binding HBXIP. Mutation of the 137CRHK140 motif in HBx abolished its ability to bind HBXIP and to dysregulate centrosome dynamics in HeLa and immortal diploid RPE-1 cells. Unlike wild-type HBx, which targets to centrosomes as determined by subcellular fractionation and immunofluorescence microscopy, HBx mutants failed to localize to centrosomes. Overexpression of viral HBx wildtype protein and knockdown of endogenous HBXIP altered centrosome assembly and induced modifications of pericentrin and centrin-2, two essential proteins required for centrosome formation and function, whereas HBXIP nonbinding mutants of HBx did not. Overexpression of HBXIP or fragments of HBXIP that bind HBx neutralized the effects of viral HBx on centrosome dynamics and spindle formation. These results suggest that HBXIP is a critical target of viral HBx for promoting genetic instability through formation of defective spindles and subsequent aberrant chromosome segregation.
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U2 - 10.1074/jbc.M708419200
DO - 10.1074/jbc.M708419200
M3 - Article
C2 - 18032378
AN - SCOPUS:41449097647
SN - 0021-9258
VL - 283
SP - 2793
EP - 2803
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 5
ER -