The linker of the nucleoskeleton and cytoskeleton (LINC) complex is composed of two transmembrane proteins: the KASH domain protein localized to the outer nuclear membrane and the SUN domain protein to the inner nuclear membrane. In budding yeast, the sole SUN domain protein, Mps3, is thought to pair with either Csm4 or Mps2, two KASH-like proteins, to form two separate LINC complexes. Here, we show that Mps2 mediates the interaction between Csm4 and Mps3 to form a heterotrimeric telomere-associated LINC (t-LINC) complex in budding yeast meiosis. Mps2 binds to Csm4 and Mps3, and all three are localized to the telomere. Telomeric localization of Csm4 depends on both Mps2 and Mps3; in contrast, Mps2's localization depends on Mps3 but not Csm4. Mps2-mediated t-LINC complex regulates telomere movement and meiotic recombination. By ectopically expressing CSM4 in vegetative yeast cells, we reconstitute the heterotrimeric t-LINC complex and demonstrate its ability to tether telomeres. Our findings therefore reveal the heterotrimeric composition of the t-LINC complex in budding yeast and have implications for understanding variant LINC complex formation.

中文翻译：

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Mps2连接Csm4和Mps3以在发芽酵母中形成端粒相关的LINC复合体。

核骨架和细胞骨架（LINC）复合体的接头由两个跨膜蛋白组成：位于外核膜的KASH域蛋白和位于内核膜的SUN域蛋白。在发芽酵母中，唯一的SUN结构域蛋白Mps3被认为与Csm4或Mps2（两个类似KASH的蛋白）配对，形成两个独立的LINC复合物。在这里，我们显示Mps2介导Csm4和Mps3之间的相互作用，从而在发芽的酵母减数分裂中形成异三聚体端粒相关的LINC（t-LINC）复合体。Mps2绑定到Csm4和Mps3，并且所有三个都定位于端粒。Csm4的端粒定位取决于Mps2和Mps3。相反，Mps2的定位取决于Mps3，而不取决于Csm4。Mps2介导的t-LINC复合物调节端粒运动和减数分裂重组。在营养酵母细胞中的CSM4，我们重构了异三聚体t-LINC复合物，并证明了其束缚端粒的能力。因此，我们的发现揭示了发芽酵母中t-LINC复合物的异三聚体组成，对理解变异LINC复合物的形成具有重要意义。