Nilsson Jakob, Sengupta Jayati, Frank Joachim, Nissen Poul
Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
EMBO Rep. 2004 Dec;5(12):1137-41. doi: 10.1038/sj.embor.7400291.
The receptor for activated C-kinase (RACK1) is a scaffold protein that is able to interact simultaneously with several signalling molecules. It binds to protein kinases and membrane-bound receptors in a regulated fashion. Interestingly, RACK1 is also a constituent of the eukaryotic ribosome, and a recent cryo-electron microscopy study localized it to the head region of the 40S subunit in the vicinity of the messenger RNA (mRNA) exit channel. RACK1 recruits activated protein kinase C to the ribosome, which leads to the stimulation of translation through the phosphorylation of initiation factor 6 and, potentially, of mRNA-associated proteins. RACK1 therefore links signal-transduction pathways directly to the ribosome, which allows translation to be regulated in response to cell stimuli. In addition, the fact that RACK1 associates with membrane-bound receptors indicates that it promotes the docking of ribosomes at sites where local translation is required, such as focal adhesions.
活化C激酶受体（RACK1）是一种支架蛋白，能够同时与多种信号分子相互作用。它以一种受调控的方式与蛋白激酶和膜结合受体结合。有趣的是，RACK1也是真核生物核糖体的组成部分，最近的一项冷冻电子显微镜研究将其定位在40S亚基的头部区域，靠近信使RNA（mRNA）出口通道。RACK1将活化的蛋白激酶C招募到核糖体，这通过起始因子6以及可能的mRNA相关蛋白的磷酸化导致翻译的刺激。因此，RACK1将信号转导途径直接与核糖体联系起来，从而使翻译能够根据细胞刺激进行调节。此外，RACK1与膜结合受体相关联这一事实表明，它促进核糖体在需要局部翻译的位点（如粘着斑）的对接。
