The interaction between Sgt1p and Skp1p is regulated by HSP90 chaperones and is required for proper CBF3 assembly
The interaction between Sgt1p and Skp1p is regulated by HSP90 chaperones and is required for proper CBF3 assembly
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DOI：
10.1128/mcb.24.20.8938-8950.2004
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发表时间：
2004-10-01
影响因子：
5.3
通讯作者：
Kaplan, KB
中科院分区：
文献类型：
--
作者：
Lingelbach, LB;Kaplan, KB
SGT1P是一种保守的蛋白质，被认为参与了许多细胞过程。发芽酵母的遗传学研究表明，SGT1在信号转导、细胞周期推进和染色体分离中发挥作用。最近的证据已经将SGT1p与HSP90伴侣联系起来，尽管这些蛋白之间的确切关系尚不清楚。为了进一步探索Sgt1p在这些过程中的作用，我们表征了Sgt1p、内部动粒复合体CBF3和HSP90伴侣之间的相互作用。我们发现SGT1p的氨基末端与CBF3亚基Skp1p和Ctf13p相互作用。HSP90与SGT1p相互作用，并与SGT1p的羧基末端结合，以核苷酸依赖的方式调节SGT1p和Skp1p之间的相互作用。虽然Sgt1p-Skp1p相互作用是CBF3组装所必需的，但稳定这种相互作用的突变阻止了对CBF3组装重要的蛋白质复合体的周转。我们认为HSP90和SGT1p共同起到分子开关的作用，维持平衡蛋白质复杂组装和周转所需的瞬时相互作用。
Sgt1p is a well-conserved protein proposed to be involved in a number of cellular processes. Genetic studies of budding yeast suggest a role for SGT1 in signal transduction, cell cycle advance, and chromosome segregation. Recent evidence has linked Sgt1p to HSP90 chaperones, although the precise relationship between these proteins is unclear. To further explore the role of Sgt1p in these processes, we have characterized the interactions among Sgt1p, the inner kinetochore complex CBF3, and HSP90 chaperones. We show that the amino terminus of Sgt1p interacts with CBF3 subunits Skp1p and Ctf13p. HSP90 interacts with Sgt1p and, in combination with the carboxy terminus of Sgt1p, regulates the interaction between Sgt1p and Skp1p in a nucleotide-dependent manner. While the Sgt1p-Skp1p interaction is required for CBF3 assembly, mutations that stabilize this interaction prevent the turnover of protein complexes important for CBF3 assembly. We propose that HSP90 and Sgt1p act together as a molecular switch, maintaining transient interactions required to balance protein complex assembly with turnover.