TIS21/BTG2/PC3 is expressed through PKC-delta pathway and inhibits binding of cyclin B1-Cdc2 and its activity, independent of p53 expression.
Signal transduction pathway and a new function of TIS21/BTG2/PC3 were investigated in p53 null U937 cells; Expression of TIS21 by 12-O-tetradecanoyl phorbol-13-acetate (TPA) stimulation was mediated by PKC-delta activation, however, was strongly inhibited by cPKC isozymes. When U937 cells were treated with TPA+Go6976, but not TPA+Go6850, the level of TIS21 mRNA was maintained over that of TPA alone. When analyzed by FACS, TPA-induced G2/M arrest was significantly inhibited by Go6850, but not by Go6976, suggesting the involvement of TIS21 and nPKC isozymes. Indeed, PKC-delta was found to be a regulator of the G2/M arrest and TIS21 expression, confirmed by employing rottlerin and dnPKC-delta experiments. In vivo accumulation of TIS21 protein significantly induced cell death through caspase 3 activation, which was supported further by degradations of procaspase 3, full-length PKC-delta, pRB, and p21(WAF1) in TIS21DeltaC expresser. When the cells were synchronized by nocodazole, TIS21 overexpressers inhibited degradations of cyclin A and cyclin B1 in 3 h after release from the synchronization. Furthermore, TIS21 inhibited cyclin B1-Cdc2 binding and its kinase activity in vivo. In summary, TPA-induced TIS21 mRNA expression is mediated by PKC-delta, and TIS21 induces G2/M arrest and cell death by inhibiting cyclin B1-Cdc2 binding and the kinase activity through its binding to Cdc2.
Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721, South Korea.
Min Sook
MS
Ryu
Myung Soog
MS
Lee
Jong Wook
JW
Hong
Tae-Ryong
TR
Hahn
Eunpyo
E
Moon
In Kyoung
IK
Lim
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002227:Carbazoles / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D019925:Cyclin A / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism*; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D016195:G2 Phase / Q000187:drug effects / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D015739:Nocodazole / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D020298:U937 Cells
C489435:Btg2 protein, mouse; C534699:CCNB1 protein, human; C493956:CDKN1A protein, human; D002227:Carbazoles; C534700:Ccnb1 protein, mouse; C493957:Cdkn1a protein, mouse; D019925:Cyclin A; D019926:Cyclin B; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D017874:Immediate-Early Proteins; D007211:Indoles; D008301:Maleimides; D011725:Pyridines; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C431843:tris(2-pyridylmethyl)amine; C081021:Go 6976; C070114:BTG2 protein, human; C497259:Prkcd protein, mouse; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D016203:CDC2 Protein Kinase; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; C070515:bisindolylmaleimide I; D015739:Nocodazole