• 제목/요약/키워드: Biological Molecular

검색결과 3,988건 처리시간 0.029초

HSV-1 ICP27 induces apoptosis by promoting Bax translocation to mitochondria through interacting with 14-3-3θ

  • Kim, Ji Ae;Kim, Jin Chul;Min, Jung Sun;Kang, Inho;Oh, Jeongho;Ahn, Jeong Keun
    • BMB Reports
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    • 제50권5호
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    • pp.257-262
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    • 2017
  • The subcellular localization of Bax plays a crucial role during apoptosis. In response to apoptotic stimuli, Bax translocates from the cytoplasm to the mitochondria, where it promotes the release of cytochrome c to the cytoplasm. In cells infected with HSV-1, apoptosis is triggered or blocked by diverse mechanisms. In this study, we demonstrate how HSV-1 ICP27 induces apoptosis and modulates mitochondrial membrane potential in HEK 293T cells. We found that ICP27 interacts with $14-3-3{\theta}$ which sequesters Bax to the cytoplasm. In addition, ICP27 promotes the translocation of Bax to the mitochondria by inhibiting the interaction between $14-3-3{\theta}$ and Bax. Our findings may provide a novel apoptotic regulatory pathway induced by ICP27 during HSV-1 infection.

Hepatitis B virus X protein enhances liver cancer cell migration by regulating calmodulin-associated actin polymerization

  • Kim, Mi-jee;Kim, Jinchul;Im, Jin-su;Kang, Inho;Ahn, Jeong Keun
    • BMB Reports
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    • 제54권12호
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    • pp.614-619
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    • 2021
  • Hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC), which is a highly aggressive cancer. HBV X protein (HBx), one of four HBV gene products, plays pivotal roles in the development and metastasis of HCC. It has been reported that HBx induces liver cancer cell migration and reorganizes actin cytoskeleton, however the molecular basis for actin cytoskeleton reorganization remains obscure. In this study, we for the first time report that HBx promotes actin polymerization and liver cancer cell migration by regulating calcium modulated protein, calmodulin (CaM). HBx physically interacts with CaM to control the level of phosphorylated cofilin, an actin depolymerizing factor. Mechanistically, HBx interacts with CaM, liberates Hsp90 from its inhibitory partner CaM, and increases the activity of Hsp90, thus activating LIMK1/cofilin pathway. Interestingly, the interaction between HBx and CaM is calcium-dependent and requires the CaM binding motif on HBx. These results indicate that HBx modulates CaM which plays a regulatory role in Hsp90/LIMK1/cofilin pathway of actin reorganization, suggesting a new mechanism of HBV-induced HCC metastasis specifically derived by HBx.

Cooperative Activity of Subunits of Human Ferritin Heteropolymers in Escherichia coli

  • Lee, Jung;Seo, Hyang-Yun;Jeon, Eun-Soon;Park, Ok-Soon;Lee, Kang-Min;Park, Chung-Ung;Kim, Kyung-Suk
    • BMB Reports
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    • 제34권4호
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    • pp.365-370
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    • 2001
  • We constructed a comparative expression system in order to produce recombinant human ferritin homo- and heteropolymers in Escherichia coli. Human ferritin H-(hfH) and L-chain (hfL) genes were expressed without amino acid changes under the control of a tac promoter. Ferritin heteropolymers of varying subunit composition were also produced by combining two different expression systems, a bicistronic expression system and a coplasmid expression system. As a result, recombinant H-chain ferritin and ferritin heteropolymers were catalytically active in forming iron core in vivo. In particular, the ferritin heteropolymer that is composed of 7% H-subunit and 93% L-subunit was capable of forming an iron core of the protein, while the L-chain ferritin homopolymer was inactive in vivo. This result indicates that the two H-subunits (i.e., 7% H-subunit content) are important to keep ferritin active in the cells. In addition, human ferritins were identified as the major iron binding proteins in the transformed cells. Also, the amount of iron bound to the recombinant ferritins was proportional to the H-subunit content in ferritin heteropolymers in vivo.

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