title: Hepatitis B virus X protein disrupts stress fiber formation and triggers apoptosis.
abstract: Cytoskeletal proteins are key participants in the cellular progression to apoptosis. In a previous study we injected nude mice with CCL13-HBx cells and identified in contrast to non-HBx transfected cells a differentially phosphorylated myosin light chain (p-MLC) by two-dimensional PAGE and mass spectrometry of the tumor material. To investigate the role of HBx in myosin light chain kinase (MLCK) signaling pathways, we analyzed the key molecules, p-MLC and MLCK, by western blotting. Immunofluorescence staining analysis showed that HBx disrupted stress fiber formation and that focal adhesion kinase (FAK) and integrin-linked kinase (ILK) were regulated by HBx-mediated phosphatase and tensin homolog (PTEN). We also used pharmacological inhibitors to explore the correlation between cytoskeletal rearrangements and HBx-mediated cell apoptosis via an MLCK and a PTEN-dependent pathway. The results showed that both ML9 and bvp restored the effects caused by HBx induction. Our findings suggest that HBx disrupts stress fiber formation and triggers apoptosis via an MLCK and a PTEN-dependent pathway.
authors.affiliation: Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chan-Yen
authors.initials: CY
authors.lastname: Kuo
authors.forename: Tzu-Yu
authors.initials: TY
authors.lastname: Chou
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Chen
authors.forename: Yung-Fong
authors.initials: YF
authors.lastname: Tsai
authors.forename: Guang-Yuh
authors.initials: GY
authors.lastname: Hwang
authors.forename: Tsong-Long
authors.initials: TL
authors.lastname: Hwang
mesh_terms: D017209:Apoptosis; D002460:Cell Line; D006515:Hepatitis B virus / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D022502:Stress Fibers / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D009219:Myosin-Light-Chain Kinase; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human