AAA-ATPase Rea1 在 60S 核糖体组装的多个阶段驱动生物发生因子的去除。

The AAA-ATPase Rea1 drives removal of biogenesis factors during multiple stages of 60S ribosome assembly.

机构信息

Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.

出版信息

Mol Cell. 2010 Jun 11;38(5):712-21. doi: 10.1016/j.molcel.2010.05.024.

The AAA(+)-ATPase Rea1 removes the ribosome biogenesis factor Rsa4 from pre-60S ribosomal subunits in the nucleoplasm to drive nuclear export of the subunit. To do this, Rea1 utilizes a MIDAS domain to bind a conserved motif in Rsa4. Here, we show that the Rea1 MIDAS domain binds another pre-60S factor, Ytm1, via a related motif. In vivo Rea1 contacts Ytm1 before it contacts Rsa4, and its interaction with Ytm1 coincides with the exit of early pre-60S particles from the nucleolus to the nucleoplasm. In vitro, Rea1's ATPase activity triggers removal of the conserved nucleolar Ytm1-Erb1-Nop7 subcomplex from isolated early pre-60S particle. We suggest that the Rea1 AAA(+)-ATPase functions at successive maturation steps to remove ribosomal factors at critical transition points, first driving the exit of early pre-60S particles from the nucleolus and then driving late pre-60S particles from the nucleus.

AAA(+)-ATP 酶 Rea1 从核质体中的前 60S 核糖体亚基中去除核糖体生物发生因子 Rsa4，以驱动亚基的核输出。为此，Rea1 利用 MIDAS 结构域结合 Rsa4 中的保守基序。在这里，我们表明 Rea1 MIDAS 结构域通过相关基序与另一个前 60S 因子 Ytm1 结合。在体内，Rea1 在与 Rsa4 结合之前与 Ytm1 接触，并且它与 Ytm1 的相互作用与早期前 60S 颗粒从核仁到核质体的出口相吻合。在体外，Rea1 的 ATP 酶活性触发从分离的早期前 60S 颗粒中去除保守的核仁 Ytm1-Erb1-Nop7 亚复合物。我们认为，Rea1 AAA(+)-ATP 酶在连续的成熟步骤中发挥作用，以在关键的过渡点去除核糖体因子，首先驱动早期前 60S 颗粒从核仁中排出，然后驱动晚期前 60S 颗粒从细胞核中排出。