Hwang Eunha, Ryu Kyoung-Seok, Pääkkönen Kimmo, Güntert Peter, Cheong Hae-Kap, Lim Dae-Sik, Lee Jie-Oh, Jeon Young Ho, Cheong Chaejoon
Magnetic Resonance Team, Korea Basic Science Institute, 804-1 Yangchung-Ri, Ochang, Chungbuk 363-883, Korea.
Proc Natl Acad Sci U S A. 2007 May 29;104(22):9236-41. doi: 10.1073/pnas.0610716104. Epub 2007 May 21.
In eukaryotic cells, apoptosis and cell cycle arrest by the Ras --> RASSF --> MST pathway are controlled by the interaction of SARAH (for Salvador/Rassf/Hippo) domains in the C-terminal part of tumor suppressor proteins. The Mst1 SARAH domain interacts with its homologous domain of Rassf1 and Rassf5 (also known as Nore1) by forming a heterodimer that mediates the apoptosis process. Here, we describe the homodimeric structure of the human Mst1 SARAH domain and its heterotypic interaction with the Rassf5 and Salvador (Sav) SARAH domain. The Mst1 SARAH structure forms a homodimer containing two helices per monomer. An antiparallel arrangement of the long alpha-helices (h2/h2') provides an elongated binding interface between the two monomers, and the short 3(10) helices (h1/h1') are folded toward that of the other monomer. Chemical shift perturbation experiments identified an elongated, tight-binding interface with the Rassf5 SARAH domain and a 1:1 heterodimer formation. The linker region between the kinase and the SARAH domain is shown to be disordered in the free protein. These results imply a novel mode of interaction with RASSF family proteins and provide insight into the mechanism of apoptosis control by the SARAH domain.
在真核细胞中，由Ras→RASSF→MST途径介导的细胞凋亡和细胞周期阻滞受肿瘤抑制蛋白C末端的SARAH（Salvador/Rassf/Hippo）结构域相互作用的控制。Mst1的SARAH结构域通过形成介导凋亡过程的异源二聚体，与其同源的Rassf1和Rassf5（也称为Nore1）结构域相互作用。在此，我们描述了人Mst1 SARAH结构域的同二聚体结构及其与Rassf5和Salvador（Sav）的SARAH结构域的异型相互作用。Mst1 SARAH结构形成一个同二聚体，每个单体包含两个螺旋。长α螺旋（h2/h2'）的反平行排列在两个单体之间提供了一个细长的结合界面，短3（10）螺旋（h1/h1'）则向另一个单体的方向折叠。化学位移扰动实验确定了与Rassf5 SARAH结构域的细长紧密结合界面以及1:1异源二聚体的形成。激酶和SARAH结构域之间的连接区域在游离蛋白中显示为无序状态。这些结果暗示了与RASSF家族蛋白相互作用的新模式，并为SARAH结构域控制细胞凋亡的机制提供了深入了解。
