Functional role of death-associated protein 3 (DAP3) in anoikis.
Detachment of adherent epithelial cells from the extracellular matrix induces apoptosis, known as anoikis. Integrin stimulation protects cells from anoikis, but the responsible mechanisms are not well known. Here, we demonstrated that a pro-apoptotic GTP-binding protein, DAP3 (death-associated protein 3), is critical for induction of anoikis. Down-regulation of DAP3 expression by antisense oligonucleotides inhibited anoikis. Conversely, overexpression of DAP3 augmented cell death and caspase activation induced by cell detachment. Furthermore, the association of DAP3 with FADD and the activation of caspase-8 were induced by cell detachment. We also showed that DAP3 is phosphorylated by kinase Akt (PKB), and active Akt can nullify apoptosis induction by DAP3. Mutation of a consensus Akt phosphorylation site in DAP3 renders it resistant to suppression by active Akt in cells. Integrin ligation stimulates Akt activation and phosphorylation of DAP3 in intact cells, as well as suppresses the ability of DAP3 overexpression to augment anoikis. Involvement of DAP3 in anoikis signaling demonstrates a novel role for this GTP-binding protein in apoptosis induction caused by cell detachment.
The Burnham Institute, La Jolla, California 92037, USA.
Tadaaki
T
Miyazaki
Min
M
Shen
Daisuke
D
Fujikura
Noriko
N
Tosa
Hyung-Ryong
HR
Kim
Shigeyuki
S
Kon
Toshimitsu
T
Uede
John C
JC
Reed
D023102:Anoikis; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D029681:Arabidopsis Proteins / Q000378:metabolism; D001665:Binding Sites; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002460:Cell Line; D015536:Down-Regulation; D004789:Enzyme Activation; D044943:Fatty Acid Desaturases / Q000378:metabolism; D020868:Gene Silencing; D005822:Genetic Vectors; D006801:Humans; D016023:Integrins / Q000378:metabolism; D008024:Ligands; D009154:Mutation; D009362:Neoplasm Metastasis; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D015398:Signal Transduction; D013912:Threonine / Q000737:chemistry; D014162:Transfection; D019096:Vitronectin / Q000378:metabolism; D014945:Wound Healing
D051017:Apoptosis Regulatory Proteins; D029681:Arabidopsis Proteins; C097041:DAP3 protein, human; D016023:Integrins; D008024:Ligands; D016376:Oligonucleotides, Antisense; D011506:Proteins; D011518:Proto-Oncogene Proteins; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D019096:Vitronectin; D013912:Threonine; D044943:Fatty Acid Desaturases; C084083:Fad7 protein, Arabidopsis; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; C505530:CASP8 protein, human; D053181:Caspase 8; D020169:Caspases