Chromatin condensation and DNA fragmentation are hallmarks of apoptotic cell death. During the past few years, two nuclear effectors of apoptosis, the DNA Fragmentation Factor (DFF) or Caspase-Activated Deoxyribonuclease (CAD), and Apoptosis Inducing Factor (AIF), have been identified. Extensive biochemical and cellular studies have established that these factors play major roles in executing the characteristic changes in nuclear morphology and integrity during apoptosis. ? ? AIF has been implicated as a caspase-independent factor, which upon release from the mitochondria, translocates to the nucleus and causes initial chromatin condensation and large fragment DNA cleavage. Targeted deletion of AIF abolishes the first wave of apoptosis indispensable for early embryonic morphogenesis, while the presence of AIF in extra-mitochondrial space is sufficient to kill cells. AIF appears to be a bifunctional protein with a resident mitochondrial function and an apoptogenic function. ? ? DFF is a molecular complex consisting of DFF40 (CAD), a novel endonuclease, and two splicing variants of its inhibitor, DFF45 (ICAD-L) and DFF35 (ICAD-S). During apoptosis, DFF45 gets cleaved by caspases, resulting in the release and activation of DFF40, which produces advanced chromatin condensation and oligo-nucleosomal DNA fragmentation. ? ? In this application, we propose to use a combination of X-ray crystallography, biochemistry and cell biology to elucidate the molecular basis of AIF and DFF function.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM066891-01
Application #
6559602
Study Section
Biophysical Chemistry Study Section (BBCB)
Program Officer
Flicker, Paula F
Project Start
2003-05-01
Project End
2007-04-30
Budget Start
2003-05-01
Budget End
2004-04-30
Support Year
1
Fiscal Year
2003
Total Cost
$288,150
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
060217502
City
New York
State
NY
Country
United States
Zip Code
10065
Park, Hyun Ho; Tookes, Hansel Emory; Wu, Hao (2006) Crystallization and preliminary X-ray crystallographic studies of Drep-3, a DFF-related protein from Drosophila melanogaster. Acta Crystallogr Sect F Struct Biol Cryst Commun 62:597-9