Bipartite interaction sites differentially modulate RNA-binding affinity of a protein complex essential for germline stem cell self-renewal.
Bipartite interaction sites differentially modulate RNA-binding affinity of a protein complex essential for germline stem cell self-renewal.
复制标题
双向相互作用位点差异性地调节生殖干细胞自我更新所必需的蛋白质复合物的RNA结合亲和力。
DOI：
10.1093/nar/gkab1220
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发表时间：
2022
影响因子：
14.9
通讯作者：
Hall,TraciMTanaka
中科院分区：
文献类型：
--
作者：
Qiu,Chen;Wine,RobertN;Campbell,ZacharyT;Hall,TraciMTanaka
因C.在线虫中，PUF 蛋白促进生殖干细胞的自我更新。它们的功能取决于与干细胞维持所必需的两种蛋白质的伙伴关系。在这里，我们重点了解重要的伴侣蛋白 LST-1 如何通过 PUF 蛋白 FBF-2 调节 mRNA。 LST-1 包含两个与 FBF-2、LST-1 A 和 B 相互作用的不同位点。我们的 FBF-2、LST-1 A 和 RNA 复合物的晶体结构可视化 FBF-2 如何与 LST-1 A 和 LST-1 B 结合。一个共同点是 FBF-2 接触 LST-1 A 和 B 中 KxxL 基序中的保守赖氨酸和亮氨酸侧链。一个关键区别是 FBF-2 形成与 KxxL 基序 N 端和 C 端区域的独特接触。因此，LST-1 A 不调节 FBF-2 的 RNA 结合亲和力，而 LST-1 B 降低 FBF-2 的 RNA 结合亲和力。 LST-1 B 的 N 端区域结合在 RNA 元件 5' 端附近，对于调节 FBF-2 RNA 结合亲和力至关重要，而 LST-1 B 的 C 端残基则对 FBF-2 提供强大的结合亲和力。我们得出的结论是，LST-1 有可能影响哪些 mRNA 受到调节，具体取决于通过其功能独特的 FBF 结合位点参与的精确性质。
InC. elegans, PUF proteins promote germline stem cell self-renewal. Their functions hinge on partnerships with two proteins that are redundantly required for stem cell maintenance. Here we focus on understanding how the essential partner protein, LST-1, modulates mRNA regulation by the PUF protein, FBF-2. LST-1 contains two nonidentical sites of interaction with FBF-2, LST-1 A and B. Our crystal structures of complexes of FBF-2, LST-1 A, and RNA visualize how FBF-2 associates with LST-1 A versus LST-1 B. One commonality is that FBF-2 contacts the conserved lysine and leucine side chains in the KxxL motifs in LST-1 A and B. A key difference is that FBF-2 forms unique contacts with regions N- and C-terminal to the KxxL motif. Consequently, LST-1 A does not modulate the RNA-binding affinity of FBF-2, whereas LST-1 B decreases RNA-binding affinity of FBF-2. The N-terminal region of LST-1 B, which binds near the 5′ end of RNA elements, is essential to modulate FBF-2 RNA-binding affinity, while the C-terminal residues of LST-1 B contribute strong binding affinity to FBF-2. We conclude that LST-1 has the potential to impact which mRNAs are regulated depending on the precise nature of engagement through its functionally distinct FBF binding sites.