Structural Basis for the Interaction of 14-3-3<i>β</i>with Tricarboxylic Acid Cycle Intermediate Malate

• 作者: Lijing Su Xiaoyan Liu Zhiqiang Hou
• 来源期刊: 生物科学与医学(英文)
• 学科: 医学
• 关键词: Crystal Structure 14-3-3 Protein CHREBP TRANSCRIPTION Activation MALATE Malic Acid
• 年，卷（期）: 2017,（8）
• 页码范围: 36-47
• 页数: 12页
• 分类号: R73

摘要

The protein family of 14-3-3(s) has risen to a position of higher importance as an adaptor protein in cell biology. The seven highly conserved human 14-3-3 proteins coordinate diverse cellular processes including apoptosis, DNA damage response, protein trafficking, and others. In liver hepatocytes, 14-3-3β binds to Ser196-phosphorilated glucose-responsive carbohydrate response element-binding protein (ChREBP) to inhibit converting excess carbohydrate to fat by regulating the nuclear/cytosol trafficking of ChREBP. Here, we report X-ray crystal structures of homodimeric mammalian 14-3-3β in its apo, Malate-bound forms. The determined apo structure was captured with one monomer in the closed state, whereas the other one had an open conformation. Strikingly, 14-3-3β binds Malate dynamically with a double-closed state, which is distinct from all previously characterized 14-3-3(s) and target ligand-binding modes. Malate docks into a first-time observed cofactor pocket located at the concaved interface of 14-3-3β helices α2, α3, α4 through mainly electrostatic and hydrogen interactions. Such a Tricarboxylic Acid Cycle intermediate Malate bond model might offer a new approach to further analyze insulin-independent 14-3-3/ChREBP pathway of de novo fat synthesis in the liver.