The proapoptotic activity of C-terminal domain of apoptosis-inducing factor (AIF) is separated from its N-terminal.
Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that mediates both NADH-oxidizing and caspase-independent apoptosis. Further, the proapoptotic activity of AIF is located in the C-terminus of AIF, although the precise minimum sequence responsible for apoptosis induction remains to be investigated. In the present study, we generated two truncated AIFs, AIFDelta1-480-FLAG, which is a FLAG-tagged C-terminal peptide comprising amino acids from 481 to 613, and AIF360-480 containing amino acids from 360 to 480 of AIF. We used confocal microscopy to demonstrate that both the truncated proteins are expressed and located in the cytoplasm of transfected cells. AIFDelta1-480 but not AIF360-480 induces apoptosis in transfected cells. We also found that the expression of AIFDelta1-480 could initiate the release of cytochrome c from the mitochondria. The suppression of caspase-9 via siRNA blocked the proapoptotic activity of AIFDelta1-480. Therefore, AIFDelta1-480 is sufficient for inducing caspase-9-dependent apoptotic signaling, probably by promoting the release of cytochrome c. At last, we generated a chimeric immuno-AIFDelta1-480 protein, which comprised an HER2 antibody, a Pseudomonas exotoxin A translocation domain and AIFDelta1-480. Human Jurkat cells transfected with the immuno-AIFDeltal-480 gene could express and secrete the chimeric protein, which selectively recognize and kill HER2-overexpressing tumor cells. Our study demonstrates the feasibility of the immuno-AIFDeltal-480 gene as a novel approach to treating HER2-overexpressing cancers.
Zhang
Yong
Y
State Key Laboratory of Cancer Biology, Department of Immunology, the Fourth Military Medical University, Xi'an, China.
Han
Tao
T
Zhu
Qing
Q
Zhang
Wei
W
Bao
Wei
W
Fu
Hai-Jing
HJ
Yang
Jie
J
Huang
Xiao-Jun
XJ
Wei
Jun-Xia
JX
Meng
Yan-Ling
YL
Zhao
Jing
J
Cao
Yun-Xin
YX
Jia
Lin-Tao
LT
Yangi
An-Gang
AG
D000429:Alcohol Oxidoreductases / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D051033:Apoptosis Inducing Factor / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D015153:Blotting, Western; D018076:DNA, Complementary / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D019169:Jurkat Cells; D018613:Microscopy, Confocal; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D051033:Apoptosis Inducing Factor; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein