Baldi A, De Luca A, Claudio P P, Baldi F, Giordano G G, Tommasino M, Paggi M G, Giordano A
Department of Microbiology/Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
J Cell Biochem. 1995 Nov;59(3):402-8. doi: 10.1002/jcb.240590311.
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/p130 protein, using a polyclonal antibody developed against its "spacer" region included in the pocket domain of the whole protein. We show that pRb2/p130 is a phosphoprotein located at the nuclear level and that its phosphorylation pathway can be dramatically reduced by phosphatase treatment. Moreover pRb2/p130 with p107, is one of the major targets of the E1A 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.
Rb2/p130蛋白已被证明与视网膜母细胞瘤基因产物（pRb）具有高度的序列同源性，pRb是特征最为明确的肿瘤抑制基因之一，它还与pRB相关的p107具有高度序列同源性，尤其是在它们保守的口袋结构域，这些结构域在这些蛋白质的功能中发挥着主要作用。在本研究中，我们使用针对整个蛋白质口袋结构域中包含的“间隔区”开发的多克隆抗体，报告了Rb2/p130蛋白的生化和免疫细胞化学特征。我们发现pRb2/p130是一种位于细胞核水平的磷蛋白，其磷酸化途径可通过磷酸酶处理显著减少。此外，pRb2/p130与p107一样，是E1A病毒癌蛋白相关激酶活性的主要靶点之一，其磷酸化模式在细胞周期中受到调节，在S期开始时达到激活峰值。
