The Rb2/p130 gene product is a nuclear protein whose phosphorylation is cycle regulated

✍ Scribed by Alfonso Baldi; Antonio De Luca; Pier Paolo Claudio; Feliciano Baldi; Giovan Giacomo Giordano; Massimo Tommasino; Marco Giorgio Paggi; Antonio Giordano

• Book ID: 102878920
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 608 KB
• Volume: 59
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240590311

✦ Synopsis

The Rb2/p130 protein has been shown to have a high sequence homology with the retinoblastoma gene product (pRb), one of the most well-characterized tumor suppressor genes, and with pRb-related p107, especially in their conserved pocket domains, which display a primary role in the function of these proteins. In this study, we report on the biochemical and immunocytochemical characterization of the Rb2/pl30 protein, using a polyclonal antibody developed against its "spacer" region included in the pocket domain of the whole protein. We show that pRb2/pl30 is a phosphoprotein located at the nuclear level and that its phosphorylation pathway can be dramatically reduced by phosphatase treatment. Moreover pRb2/pl30, with p107, is one of the major targets of the E I A viral oncoprotein-associated kinase activity, showing a phosphorylation pattern which is modulated during the cell cycle, reaching a peak of activation at the onset of S-phase.