The long term goal of this proposed research is to understand the mechanisms of apoptosis in malignant and primary T cells. Fas is a member of the tumor necrosis factor receptor superfamily and is expressed on activated T cells and many malignant cells. Treatment with anti-Fas antibody leads to apoptosis in many but not all the tumor cells. A similar situation can also be found for T cells from different developmental stages. Immature T cells is particularly susceptible to Fas-induced apoptosis while mature T cells are quite resistant to the apoptotic-effect of anti-Fas antibodies. Mort 1 /FADD is a protein with a death domain, a protein-protein interaction domain that is also found in the cytoplasmic tail of Fas and tumor necrosis factor receptor p55. In sensitive cells, addition of anti-Fas antibodies triggers Mort1 to associate with Fas. Interference of this association process by a dominant negative Mort1 protein leads to inhibition of apoptosis. In several malignant cell lines that are resistant to Fas-mediated apoptosis, Mortl was found not to associate with Fas. Thus, Mortl-Fas association is a key step in Fas-induced apoptosis that might determine susceptibility of a cell to anti-Fas-mediated cell death. Lymphomas, thymomas and T cell hybridomas as well as transgenic and gene-targeted mutant mice will be used to understand the role of Mortl in apoptosis of malignant and primary T cells. The following specific aims are proposed. First, structure-function analysis of the Mortl protein will be performed using a Fas/Mortl chimeric protein. Second, the molecular process of Mortl/Fas association will be examined in malignant and primary T cells. Third, Mortl-deficient mice will be generated and analyzed. Fourth, the role of Mort I and one of its associating protein in apoptosis of immature T cells will be examined. The above aims should lead to a better understanding of the mechanisms of peripheral and central tolerance and why some tumor cells are resistant to Fas-induced apoptosis. The information obtained might lead to means by which apoptosis in resistant tumor cells might be induced and to halting of the onset of cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA075162-04
Application #
6173506
Study Section
Experimental Immunology Study Section (EI)
Program Officer
Mccarthy, Susan A
Project Start
1997-08-05
Project End
2002-05-31
Budget Start
2000-06-01
Budget End
2001-05-31
Support Year
4
Fiscal Year
2000
Total Cost
$225,824
Indirect Cost
Name
University of California Berkeley
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Alappat, Elizabeth C; Feig, Christine; Boyerinas, Benjamin et al. (2005) Phosphorylation of FADD at serine 194 by CKIalpha regulates its nonapoptotic activities. Mol Cell 19:321-32
Xing, Zheng; Conway, Edward M; Kang, Chulho et al. (2004) Essential role of survivin, an inhibitor of apoptosis protein, in T cell development, maturation, and homeostasis. J Exp Med 199:69-80
Sohn, Sue J; Rajpal, Arvind; Winoto, Astar (2003) Apoptosis during lymphoid development. Curr Opin Immunol 15:209-16
Hua, Zi Chun; Sohn, Sue J; Kang, Chulho et al. (2003) A function of Fas-associated death domain protein in cell cycle progression localized to a single amino acid at its C-terminal region. Immunity 18:513-21
Kabra, N H; Kang, C; Hsing, L C et al. (2001) T cell-specific FADD-deficient mice: FADD is required for early T cell development. Proc Natl Acad Sci U S A 98:6307-12
Zhang, J; Kabra, N H; Cado, D et al. (2001) FADD-deficient T cells exhibit a disaccord in regulation of the cell cycle machinery. J Biol Chem 276:29815-8
Kuang, A A; Diehl, G E; Zhang, J et al. (2000) FADD is required for DR4- and DR5-mediated apoptosis: lack of trail-induced apoptosis in FADD-deficient mouse embryonic fibroblasts. J Biol Chem 275:25065-8
Kabra, N H; Cado, D; Winoto, A (1999) A tailless fas-FADD death-effector domain chimera is sufficient to execute Fas function in T cells but not B cells of MRL-lpr/lpr mice. J Immunol 162:2766-74