DNA binding is required for the apoptogenic action of apoptosis inducing factor.
The execution of apoptosis or programmed cell death comprises both caspase-dependent and caspase-independent processes. Apoptosis inducing factor (AIF) was identified as a major player in caspase-independent cell death. It induces chromatin condensation and initial DNA cleavage via an unknown molecular mechanism. Here we report the crystal structure of human AIF at 1.8 A resolution. The structure reveals the presence of a strong positive electrostatic potential at the AIF surface, although the calculated isoelectric point for the entire protein is neutral. We show that recombinant AIF interacts with DNA in a sequence-independent manner. In addition, in cells treated with an apoptotic stimulus, endogenous AIF becomes co-localized with DNA at an early stage of nuclear morphological changes. Structure-based mutagenesis shows that DNA-binding defective mutants of AIF fail to induce cell death while retaining nuclear translocation. The potential DNA-binding site identified from mutagenesis also coincides with computational docking of a DNA duplex. These observations suggest that AIF-induced nuclear apoptosis requires a direct interaction with DNA.
Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10021, USA.
Hong
H
Ye
Celine
C
Cande
Nicolas C
NC
Stephanou
Sulin
S
Jiang
Sundeep
S
Gurbuxani
Nathanael
N
Larochette
Eric
E
Daugas
Carmen
C
Garrido
Guido
G
Kroemer
Hao
H
Wu
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051033:Apoptosis Inducing Factor; D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism*; D005420:Flavoproteins / Q000737:chemistry / Q000502:physiology*; D008565:Membrane Proteins / Q000737:chemistry / Q000502:physiology*; D051379:Mice; D011485:Protein Binding; D011487:Protein Conformation; D055672:Static Electricity
D051033:Apoptosis Inducing Factor; D005420:Flavoproteins; D008565:Membrane Proteins; C494830:AIFM1 protein, mouse; D004247:DNA