Tobacco RETINOBLASTOMA-RELATED protein is phosphorylated by different types of cyclin-dependent kinases during the cell cycle
Plants contain a regulatory pathway similar to that involving retinoblastoma (RB) protein in animals. Here, we analyze an <i>RB</i> homolog, tobacco <i>RETINOBLASTOMA-RELATED1</i> (<i>NtRBR1</i>), that encodes a protein possessing 13 potential phosphorylation sites for cyclin-dependent kinases (CDKs). We found that 11 synthetic peptides containing sequences from NtRBR1 were phosphorylated differentially by imunoprecipitates of cyclin/CDK complexes extracted from tobacco BY-2 cells. We raised antibodies that specifically recognize these sites of phosphorylation in NtRBR1. Distinct sites were phosphorylated during the cell cycle, suggesting that NtRBR1 is phosphorylated by different types of cyclin/CDK complexes.
- Plant biotechnology
Plant biotechnology 23(5), 467-473, 2006-12-01
Japanese Society for Plant Cell and Molecular Biology