TY - JOUR
T1 - Physical interaction between pRb and cdk9/cyclinT2 complex
AU - Simone, Cristiano
AU - Bagella, Luigi
AU - Bellan, Cristiana
AU - Giordano, Antonio
PY - 2002/6/13
Y1 - 2002/6/13
N2 - Cyclin-dependent kinase 9 (cdk9) is a multifunctional kinase with roles in different cellular pathways such as transcriptional elongation, differentiation and apoptosis. Cdk9/cyclin T differs functionally from other cdk/cyclin complexes that regulate cell cycle progression, but maintains structural affinity with those complexes. In addition, previous reports have demonstrated that the cdk9 complex is able to phosphorylate p56/pRb in vitro. In this report we show in vitro and in vivo interaction between cdk9/cyclinT2 and the protein product of the retinoblastoma gene (pRb) in human cell lines. The interaction involves the region composed of residues 129-195 of cdk9, cyclinT2 (1-642 aa) and the C-terminal domain of pRb (835-928 aa). We located the minimal region of cdk9 phosphorylation on the C-terminus of pRb, by identifying the residues between 793 and 834. This region contains at least three proline-directed serines (sp), S795, S807 and S811, which have been reported to be phosphorylated in vivo and which could be targeted by the cdk9 complex. These data suggest that, in logarithmically growing cells, cdk9/cyclin T2 and pRb are located in a nuclear multiprotein complex probably involved in transduction of cellular signals to the basal transcription machinery and that one of these signals could be the cdk9 phosphorylation of pRb.
AB - Cyclin-dependent kinase 9 (cdk9) is a multifunctional kinase with roles in different cellular pathways such as transcriptional elongation, differentiation and apoptosis. Cdk9/cyclin T differs functionally from other cdk/cyclin complexes that regulate cell cycle progression, but maintains structural affinity with those complexes. In addition, previous reports have demonstrated that the cdk9 complex is able to phosphorylate p56/pRb in vitro. In this report we show in vitro and in vivo interaction between cdk9/cyclinT2 and the protein product of the retinoblastoma gene (pRb) in human cell lines. The interaction involves the region composed of residues 129-195 of cdk9, cyclinT2 (1-642 aa) and the C-terminal domain of pRb (835-928 aa). We located the minimal region of cdk9 phosphorylation on the C-terminus of pRb, by identifying the residues between 793 and 834. This region contains at least three proline-directed serines (sp), S795, S807 and S811, which have been reported to be phosphorylated in vivo and which could be targeted by the cdk9 complex. These data suggest that, in logarithmically growing cells, cdk9/cyclin T2 and pRb are located in a nuclear multiprotein complex probably involved in transduction of cellular signals to the basal transcription machinery and that one of these signals could be the cdk9 phosphorylation of pRb.
KW - cdk9
KW - Cyclin T2
KW - Phosphorylation
KW - pRb
UR - http://www.scopus.com/inward/record.url?scp=0037071899&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037071899&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1205511
DO - 10.1038/sj.onc.1205511
M3 - Article
C2 - 12037672
AN - SCOPUS:0037071899
VL - 21
SP - 4158
EP - 4165
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 26
ER -