McMullin T W, Hallberg R L
Mol Cell Biol. 1986 Jul;6(7):2527-35. doi: 10.1128/mcb.6.7.2527-2535.1986.
After a nonlethal but heat shock protein-inducing hyperthermic treatment, ribosomes isolated from Tetrahymena thermophila contained an additional 22-kilodalton protein (p22). When maximally ribosome associated, this protein was found to be on the small subunit in a 1:1 stoichiometric ratio with other ribosomal proteins. Using an antiserum directed against the purified 22-kilodalton protein, we found that non-heat-shocked and heat-shocked cells contain identical amounts of this protein, the only difference being that in the stressed cells p22 is entirely ribosome bound, whereas in the unstressed cells p22 has little or no detectable ribosome association. Because the two-dimensional electrophoretic properties of p22 showed no alterations after heat shock, this change in state of ribosome-p22 interaction does not appear to be caused by a chemical modification of p22. When not strongly ribosome associated, p22 is not found free in the cytoplasm. During that time in heat shock when p22 is first becoming ribosome associated, it is found preferentially on polysomal ribosomes. Subsequently, all ribosomes, whether polysome bound or not, obtain a bound p22. The functional significance of this association is discussed.
在进行了一次非致死性但能诱导热休克蛋白的高温处理后，从嗜热四膜虫中分离出的核糖体含有一种额外的22千道尔顿蛋白（p22）。当该蛋白与核糖体最大程度结合时，发现它存在于小亚基上，与其他核糖体蛋白的化学计量比为1:1。使用针对纯化的22千道尔顿蛋白的抗血清，我们发现未受热休克和受热休克的细胞中该蛋白的含量相同，唯一的区别在于，在应激细胞中p22完全与核糖体结合，而在未应激细胞中p22几乎没有或没有可检测到的核糖体结合。由于热休克后p22的二维电泳特性没有改变，核糖体 - p22相互作用状态的这种变化似乎不是由p22的化学修饰引起的。当不与核糖体强烈结合时，在细胞质中未发现游离的p22。在热休克期间，当p22刚开始与核糖体结合时，优先在多聚核糖体上发现它。随后，所有核糖体，无论是否与多聚体结合，都获得了结合的p22。本文讨论了这种结合的功能意义。
