Pat1 promotes the activation and assembly of multiple proteins during mRNA decay. After deadenylation, the Pat1/Lsm1-7 complex binds to transcripts containing oligo(A) tails, which can be modified by the addition of several terminal uridine residues. Pat1 enhances Lsm1-7 binding to the 3' end, but it is unknown how this interaction is influenced by nucleotide composition. Here we examine Pat1/Lsm1-7 binding to a series of oligoribonucleotides containing different A/U contents using recombinant purified proteins from fission yeast. We observe a positive correlation between fractional uridine content and Lsm1-7 binding affinity. Addition of Pat1 broadens RNA specificity of Lsm1-7 by enhancing binding to A-rich RNAs and increases cooperativity on all oligonucleotides tested. Consistent with increased cooperativity, Pat1 promotes multimerization of the Lsm1-7 complex, which is potentiated by RNA binding. Furthermore, the inherent ability of Pat1 to multimerize drives liquid-liquid phase separation with multivalent decapping enzyme complexes of Dcp1/Dcp2. Our results uncover how Pat1 regulates RNA binding and higher order assembly by mRNA decay factors.

中文翻译：

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Pat1 增加了 Lsm1-7 复合物结合的衰变因子和 RNA 的范围

Pat1 在 mRNA 衰变过程中促进多种蛋白质的激活和组装。去腺苷酸化后，Pat1/Lsm1-7 复合物与含有 oligo(A) 尾巴的转录物结合，可通过添加几个末端尿苷残基来修饰。Pat1 增强了 Lsm1-7 与 3' 末端的结合，但尚不清楚这种相互作用如何受核苷酸组成的影响。在这里，我们使用来自裂殖酵母的重组纯化蛋白检查 Pat1/Lsm1-7 与一系列含有不同 A/U 含量的寡核糖核苷酸的结合。我们观察到尿苷含量与 Lsm1-7 结合亲和力之间呈正相关。添加 Pat1 通过增强与富含 A 的 RNA 的结合来拓宽 Lsm1-7 的 RNA 特异性，并增加对所有测试寡核苷酸的协同性。与增加的合作性相一致，Pat1 促进 Lsm1-7 复合物的多聚化，其通过 RNA 结合增强。此外，Pat1 固有的多聚化能力通过 Dcp1/Dcp2 的多价脱帽酶复合物驱动液-液相分离。我们的结果揭示了 Pat1 如何通过 mRNA 衰减因子调节 RNA 结合和高阶组装。