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The Role of Lipid Raft-Translocation of Prohibitin in Regulation of Akt and Raf-Protected Apoptosis of HaCaT Cells upon Ultraviolet B Irradiation

Wu, Qiong
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1382638433

Abstract Details

2013, Doctor of Philosophy (PhD), Ohio University, Chemistry and Biochemistry (Arts and Sciences).
Modification of major lipid raft components, such as cholesterol and ceramide, plays a role in regulation of Ultraviolet B light (UVB)-induced apoptosis. Upon UVB irradiation, an alternation of major lipid raft components can lead to the recruitment/activation of raft-associated proteins and initiation of downstream apoptotic signaling pathways. To identify potential regulators of UVB-induced apoptosis, we used two-dimensional gel electrophoresis and mass spectrometry fingerprint analysis to identify proteins that are altered in the rafts after UVB irradiation. Our data shows that levels of several proteins, including prohibitin (PHB), were changed in lipid rafts after UVB irradiation. PHB plays a critical role in many cell functions, such as cell-cycle control, cell proliferation, senescence, development, apoptosis, and tumor suppression. However, until now, no report has identified a role for PHB in mediating apoptosis upon UVB irradiation. We now demonstrate that while total and cell surface PHB expression was not changed, the protein was enriched in lipid rafts after UVB irradiation. Reduced expression of PHB using siRNA knockdown resulted in an increase in apoptosis after UVB irradiation. To reveal the detailed mechanism for PHB-mediated apoptosis upon UVB irradiation, we evaluate whether PHB is involved in regulation of Akt and Raf activity as well as oxidative stress in UVB-irradiated HaCaT cells. Our data shows that upon UVB irradiation PHB is translocated to the lipid rafts, which is correlated with a release of both Akt and Raf from membrane. Overexpression of Akt and/or Raf impedes UVB-induced lipid rafts translocation of PHB. Immunoprecipitation analysis indicates that UVB alters the interactions among PHB, Akt, and Raf. Reduced expression of PHB leads to a decreased phosphorylation of Akt and ERK, as well as a decreased activity of Akt, and an increased apoptosis of the cells after UVB irradiation. In addition, our data shows that the effect of LNAC on UVB-mediated apoptosis and proliferation is independent of PHB knockdown, suggesting an alternative pathway independent of UVB-induced oxidative stress. These results suggested that PHB regulates UVB-induced apoptosis of keratinocytes via a mechanism that involves detachment from Akt and Raf on the plasma membrane, and sequentially lipid rafts translocation.
Shiyong Wu (Advisor)
Marcia Kieliszewski (Committee Member)
Hao Chen (Committee Member)
Monica Burdick (Committee Member)
117 p.
Biochemistry; Biology; Cellular Biology; Molecular Biology
ultraviolet B; lipid raft; prohibitin; apoptosis

Recommended Citations

Citations

  • Wu, Q. (2013). The Role of Lipid Raft-Translocation of Prohibitin in Regulation of Akt and Raf-Protected Apoptosis of HaCaT Cells upon Ultraviolet B Irradiation [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1382638433

    APA Style (7th edition)

  • Wu, Qiong. The Role of Lipid Raft-Translocation of Prohibitin in Regulation of Akt and Raf-Protected Apoptosis of HaCaT Cells upon Ultraviolet B Irradiation. 2013. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1382638433.

    MLA Style (8th edition)

  • Wu, Qiong. "The Role of Lipid Raft-Translocation of Prohibitin in Regulation of Akt and Raf-Protected Apoptosis of HaCaT Cells upon Ultraviolet B Irradiation." Doctoral dissertation, Ohio University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1382638433

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Ohio University and OhioLINK.