Determinants of 14-3-3σ Protein Dimerization and Function in Drug and Radiation Resistance
Determinants of 14-3-3σ Protein Dimerization and Function in Drug and Radiation Resistance
复制标题
DOI：
10.1074/jbc.m113.467753
复制
发表时间：
2013-11-01
影响因子：
4.8
通讯作者：
Zhang, Jian-Ting
中科院分区：
文献类型：
--
作者：
Li, Zhaomin;Peng, Hui;Zhang, Jian-Ting
许多蛋白质以同二聚体的形式存在并发挥作用。了解驱动同二聚化的详细机制非常重要，并将影响未来针对“不可成药”致癌蛋白二聚体的研究。在本研究中，我们使用 14-3-3 sigma 作为同二聚蛋白模型，并对同二聚化界面中氨基酸残基的潜在作用进行了系统研究。与保守的 14-3-3 蛋白家族的其他成员不同，14-3-3 sigma 更喜欢形成同型二聚体，其二聚体界面中有两个分区，具有 180 度对称性。我们发现二聚体界面的两个分区都需要维持完整的二聚化活性。尽管界面疏水核心残基Leu(12)和Tyr(84)在14-3-3σ二聚化中发挥重要作用，但非核心残基Phe(25)似乎在控制14-3-3σ二聚化活性中更重要。有趣的是，类似的非核心残基 (Val(81)) 在促进 14-3-3 σ 二聚化方面不如 Phe(25) 重要。此外，通过分别突变Leu(12)、Phe(25)或Tyr(84)二聚残基，将二聚体14-3-3 sigma解离成单体，会削弱14-3-3 sigma抵抗药物诱导的细胞凋亡以及将细胞阻滞在G(2)/M期以响应DNA损伤治疗的功能。因此，二聚化似乎是 14-3-3 σ 功能所必需的。
Many proteins exist and function as homodimers. Understanding the detailed mechanism driving the homodimerization is important and will impact future studies targeting the "undruggable" oncogenic protein dimers. In this study, we used 14-3-3 sigma as a model homodimeric protein and performed a systematic investigation of the potential roles of amino acid residues in the interface for homodimerization. Unlike other members of the conserved 14-3-3 protein family, 14-3-3 sigma prefers to form a homodimer with two subareas in the dimeric interface that has 180 degrees symmetry. We found that both subareas of the dimeric interface are required to maintain full dimerization activity. Although the interfacial hydrophobic core residues Leu(12) and Tyr(84) play important roles in 14-3-3 sigma dimerization, the non-core residue Phe(25) appears to be more important in controlling 14-3-3 sigma dimerization activity. Interestingly, a similar non-core residue (Val(81)) is less important than Phe(25) in contributing to 14-3-3 sigma dimerization. Furthermore, dissociating dimeric 14-3-3 sigma into monomers by mutating the Leu(12), Phe(25), or Tyr(84) dimerization residue individually diminished the function of 14-3-3 sigma in resisting drug-induced apoptosis and in arresting cells at G(2)/M phase in response to DNA-damaging treatment. Thus, dimerization appears to be required for the function of 14-3-3 sigma.