| First Author | Proteau A | Year | 2005 |
| Journal | J Mol Biol | Volume | 346 |
| Issue | 4 | Pages | 1163-72 |
| PubMed ID | 15701524 | Mgi Jnum | J:96797 |
| Mgi Id | MGI:3531592 | Doi | 10.1016/j.jmb.2004.12.034 |
| Citation | Proteau A, et al. (2005) The multifunctional nuclear protein p54nrb is multiphosphorylated in mitosis and interacts with the mitotic regulator Pin1. J Mol Biol 346(4):1163-72 |
| abstractText | The human protein p54nrb and its mouse homolog NonO have been implicated in a variety of nuclear processes including transcription, pre-mRNA processing, nuclear retention of edited RNA and DNA relaxation. We have identified p54nrb as an antigen of the phosphodependent monoclonal antibodies CC-3 and MPM-2 and shown that this protein is phosphorylated on multiple sites during mitosis. The use of the cyclin-dependent protein kinase inhibitor roscovitine and immunodepletion studies with an anti-cyclin B1 antibody established that Cdk1 was responsible for the phosphorylation of the carboxy-terminal extremity of p54nrb whereas a different kinase appeared to be involved in the generation of CC-3 epitope(s) in the amino-terminal moiety of the protein. Like many CC-3 and MPM-2 antigens, we show that p54nrb is a target of the peptidylprolyl isomerase Pin1, suggesting that it may be regulated by phosphorylation-dependent conformational changes as many other nuclear proteins upon entry into mitosis. In addition, site-directed mutagenesis indicated that the interaction of Pin1 with p54nrb was mediated by three threonine residues located in the proline-rich carboxy-terminal extremity of the protein. Our results also showed that Pin1 binding was favored when at least two of the three threonine residues were phosphorylated, suggesting a regulation mechanism based on multisite phosphorylation. |
