Las1 interacts with Grc3 polynucleotide kinase and is required for ribosome synthesis in Saccharomyces cerevisiae
Las1 interacts with Grc3 polynucleotide kinase and is required for ribosome synthesis in Saccharomyces cerevisiae
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DOI：
10.1093/nar/gks1086
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发表时间：
2013-01-01
影响因子：
14.9
通讯作者：
Denicourt, Catherine
中科院分区：
文献类型：
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作者：
Castle, Christopher D.;Sardana, Richa;Denicourt, Catherine
核糖体生物发生是一个将细胞生长与细胞增殖结合起来的多步骤过程。尽管对前核糖体颗粒的一些大规模分析已经鉴定出许多参与该过程的反式作用因子，但许多参与前rRNA加工和核糖体亚基成熟的蛋白质尚未被鉴定。 Las1 最初在酿酒酵母中被鉴定为参与细胞形态发生的蛋白质。我们之前证明，人类同源物 Las1L 是有效 ITS2 rRNA 加工和 60S 核糖体亚基合成所必需的。在这里，我们报告Las1在核糖体生物发生中的功能在酿酒酵母中也被保守。 Las1 的缺失导致 27S 和 7S rRNA 中间体的积累，并损害 60S 亚基的合成。我们发现 Las1 主要与 27S rRNA 共沉淀，并与包含 Nsa1 和 Rix1 的前 60S 颗粒结合。我们进一步确定 Grc3 是主要的 Las1 相互作用蛋白。我们证明，Grc3 的激酶活性是有效前 rRNA 加工所必需的，并且 Grc3 的耗尽会导致 rRNA 加工缺陷，类似于在 Las1 耗尽的细胞中观察到的缺陷。我们提出 Las1 和 Grc3 以保守机制共同发挥作用，调节 rRNA 加工和真核核糖体生物合成。
Ribosome biogenesis is a multi-step process that couples cell growth with cell proliferation. Although several large-scale analysis of pre-ribosomal particles have identified numerous trans-acting factors involved in this process, many proteins involved in pre-rRNA processing and ribosomal subunit maturation have yet to be identified. Las1 was originally identified in Saccharomyces cerevisiae as a protein involved in cell morphogenesis. We previously demonstrated that the human homolog, Las1L, is required for efficient ITS2 rRNA processing and synthesis of the 60S ribosomal subunit. Here, we report that the functions of Las1 in ribosome biogenesis are also conserved in S. cerevisiae. Depletion of Las1 led to the accumulation of both the 27S and 7S rRNA intermediates and impaired the synthesis of the 60S subunit. We show that Las1 co-precipitates mainly with the 27S rRNA and associates with an Nsa1 and Rix1-containing pre-60S particle. We further identify Grc3 as a major Las1-interacting protein. We demonstrate that the kinase activity of Grc3 is required for efficient pre-rRNA processing and that depletion of Grc3 leads to rRNA processing defects similar to the ones observed in Las1-depleted cells. We propose that Las1 and Grc3 function together in a conserved mechanism to modulate rRNA processing and eukaryotic ribosome biogenesis.