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B-CELL LYMPHOMA-2 PROTEIN FAMILY, APOPTOSIS AND THE ENDOPLASMIC RETICULUM

Thomenius, Michael James

Abstract Details

2004, Doctor of Philosophy, Case Western Reserve University, Pharmacology.
The Bcl-2 oncogene encodes a protein that inhibits apoptosis or programmed cell death. Apoptosis is a process critical for development and tissue homeostasis and is of great importance to cancer chemotherapy. The molecular mechanisms of apoptosis are still poorly understood, but it is known that a number of events occur on mitochondria such as membrane permeabilization and release of intermembrane space proteins into the cytoplasm. These mitochondrial events are regulated by the Bcl-2 family of proteins. This family is made up of an anti-apoptotic subfamily (Bcl-2, Bcl-xL, Mcl-1) and two pro-apoptotic subfamilies, the multidomain pro-apoptotic proteins (Bax, Bak, Bok) and the BH3-only subfamily (Bid, Bim, Bik, Bad). These proteins were initially thought to function on the mitochondria to regulate mitochondrial events of cell death, but it has subsequently been shown that Bcl- 2 family members can regulate cell death when localized to the endoplasmic reticulum (ER). The work presented here shows that Bcl-2 localized to the ER can inhibit the activation of mitochondria-localized Bax, indicating that an intermediate must exist between the ER and mitochondria. This work also shows that Bcl-2 localized to the ER can bind to BH3-only proteins preventing them from activating Bax on the mitochondria. In addition to anti-apoptotic proteins, it was determined that the pro-apoptotic cleavage fragment of Bcl-2, deltaBH4 could induce apoptosis when localized to the ER, but with less potency than deltaBH4 localized to both the mitochondria and the ER. This work also demonstrates that deltaBH4 and deltaBH4 on the ER can induce the depletion of ER calcium, suggesting a probable mechanism for their toxicity. These data, taken together suggest a model whereby the Bcl-2 family works to regulate ER to mitochondrial communication during apoptosis.
Clark Distelhorst (Advisor)
179 p.

Recommended Citations

Citations

  • Thomenius, M. J. (2004). B-CELL LYMPHOMA-2 PROTEIN FAMILY, APOPTOSIS AND THE ENDOPLASMIC RETICULUM [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1080679967

    APA Style (7th edition)

  • Thomenius, Michael. B-CELL LYMPHOMA-2 PROTEIN FAMILY, APOPTOSIS AND THE ENDOPLASMIC RETICULUM. 2004. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1080679967.

    MLA Style (8th edition)

  • Thomenius, Michael. "B-CELL LYMPHOMA-2 PROTEIN FAMILY, APOPTOSIS AND THE ENDOPLASMIC RETICULUM." Doctoral dissertation, Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1080679967

    Chicago Manual of Style (17th edition)