Chemosensitization by a non-apoptogenic heat shock protein 70-binding apoptosis-inducing factor mutant.
Heat shock protein 70 (HSP70) inhibits apoptosis and thereby increases the survival of cells exposed to a wide range of lethal stimuli. HSP70 has also been shown to increase the tumorigenicity of cancer cells in rodent models. The protective function of this chaperone involves interaction and neutralization of the caspase activator apoptotic protease activation factor-1 and the mitochondrial flavoprotein apoptosis-inducing factor (AIF). In this work, we determined by deletional mutagenesis that a domain of AIF comprised between amino acids 150 and 228 is engaged in a molecular interaction with the substrate-binding domain of HSP70. Computer calculations favored this conclusion. On the basis of this information, we constructed an AIF-derived protein, which is cytosolic, noncytotoxic, yet maintains its capacity to interact with HSP70. This protein, designated ADD70, sensitized different human cancer cells to apoptosis induced by a variety of death stimuli by its capacity to interact with HSP70 and therefore to sequester HSP70. Thus, its chemosensitizing effect was lost in cells in which inducible HSP70 genes had been deleted. These data delineate a novel strategy for the selective neutralization of HSP70.
Schmitt
Elise
E
Institut National de la Santé et de la Recherché Médicale U-517, Faculty of Medicine and Pharmacy, Dijon, France.
Parcellier
Arnaud
A
Gurbuxani
Sandeep
S
Cande
Celine
C
Hammann
Arlette
A
Morales
Maria Celia
MC
Hunt
Clayton R
CR
Dix
David J
DJ
Kroemer
Romano T
RT
Giordanetto
Fabrizio
F
Jäättelä
Marja
M
Penninger
Josef M
JM
Pance
Alena
A
Kroemer
Guido
G
Garrido
Carmen
C
D017209:Apoptosis / Q000502:physiology; D051033:Apoptosis Inducing Factor; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D003198:Computer Simulation; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016296:Mutagenesis; D010449:Peptide Mapping; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D014162:Transfection
D051033:Apoptosis Inducing Factor; D005420:Flavoproteins; D018840:HSP70 Heat-Shock Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D049452:Green Fluorescent Proteins; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases