Mihara K, Cao X R, Yen A, Chandler S, Driscoll B, Murphree A L, T'Ang A, Fung Y K
Division of Hematology/Oncology and Ophthalmology, Childrens Hospital of Los Angeles, CA.
Science. 1989 Dec 8;246(4935):1300-3. doi: 10.1126/science.2588006.
The human retinoblastoma gene (RB1) encodes a protein (Rb) of 105 kilodaltons that can be phosphorylated. Analysis of Rb metabolism has shown that the protein has a half-life of more than 10 hours and is synthesized at all phases of the cell cycle. Newly synthesized Rb is not extensively phosphorylated (it is "underphosphorylated") in cells in the G0 and G1 phases but is phosphorylated at multiple sites at the G1/S boundary and in S phase. HL-60 cells that were induced to terminally differentiate by various chemicals lost their ability to phosphorylate newly synthesized Rb at multiple sites when cell growth was arrested. These findings suggest that underphosphorylated Rb may restrict cell proliferation.
人类视网膜母细胞瘤基因（RB1）编码一种105千道尔顿的可磷酸化蛋白质（Rb）。对Rb代谢的分析表明，该蛋白质的半衰期超过10小时，且在细胞周期的所有阶段都有合成。新合成的Rb在G0期和G1期细胞中没有广泛磷酸化（即“低磷酸化”），但在G1/S边界和S期会在多个位点发生磷酸化。当细胞生长停滞时，经各种化学物质诱导终末分化的HL-60细胞失去了在多个位点对新合成的Rb进行磷酸化的能力。这些发现表明，低磷酸化的Rb可能会限制细胞增殖。
