The SET protein regulates G2/M transition by modulating cyclin B-cyclin-dependent kinase 1 activity.
The SET protein and the cell cycle inhibitor p21(Cip1) interact in vivo and in vitro. We identified here the domain (157)LIF(159) of p21(Cip1) as essential for the binding of SET. We also found that SET contains at least two domains of interaction with p21(Cip1), one located in the fragment amino acids 81-180 and the other one in the fragment including amino acids 181-277. SET and p21(Cip1) co-localize in the cell nucleus in a temporal manner. Overexpression of SET blocks the cell cycle at the G(2)/M transition in COS and HCT116 cells. Moreover, SET inhibits cyclin B-CDK1 activity both in vivo and in vitro in both cell types. This effect is specific for these complexes since SET did not inhibit either cyclin A-CDK2 or cyclin E-CDK2 complexes. SET and p21(Cip1) cooperate in the inhibition of cyclin B-CDK1 activity. The inhibitory effect of SET resides in its acidic C terminus, as demonstrated by the ability of this domain to inhibit cyclin B-CDK1 activity and by the lack of blocking G(2)/M transition when a mutated form of SET lacking this C terminus domain was overexpressed in COS cells. These results indicate that SET might regulate G(2)/M transition by modulating cyclin B-CDK1 activity.
Canela
Núria
N
Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Institut d'Investigacions Biomèdiques August Pi Sunyer, Universitat de Barcelona, Casanova 143, Spain.
Rodriguez-Vilarrupla
Aina
A
Estanyol
Josep Maria
JM
Diaz
Carmen
C
Pujol
María Jesús
MJ
Agell
Neus
N
Bachs
Oriol
O
D000818:Animals; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000502:physiology*; D019556:COS Cells; D002868:Chromosomal Proteins, Non-Histone; D019926:Cyclin B / Q000037:antagonists & inhibitors / Q000502:physiology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000502:physiology; D004268:DNA-Binding Proteins; D016195:G2 Phase; D056488:Histone Chaperones; D006801:Humans; D008938:Mitosis; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D014157:Transcription Factors; D014162:Transfection
C493956:CDKN1A protein, human; D002868:Chromosomal Proteins, Non-Histone; D019926:Cyclin B; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D056488:Histone Chaperones; D011506:Proteins; C513473:SET protein, human; D014157:Transcription Factors; D016203:CDC2 Protein Kinase