Structural insight into TIPE1 functioning as a lipid transfer protein
Structural insight into TIPE1 functioning as a lipid transfer protein
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DOI：
10.1080/07391102.2023.2187641
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发表时间：
2023-03-04
影响因子：
4.4
通讯作者：
Wang，Wei
中科院分区：
文献类型：
--
作者：
Cao，Sujian;Zhang，Ye;Wang，Wei
TIPE 1是肿瘤坏死因子-α诱导蛋白8（TNFAIP 8/TIPE）家族的成员之一，与细胞凋亡、自噬和肿瘤发生等多种细胞信号通路相关。然而，TIPE 1在信令网络中的位置仍然难以捉摸。在这里，我们提出的晶体结构的斑马鱼TIPE 1与磷脂酰乙醇胺（PE）的复杂的分辨率为1.38毫微米。通过与其他三种TIPE家族蛋白结构的比较，提出了一种通用的磷脂结合模式。也就是说，疏水空腔与脂肪酸尾部结合，而空腔入口附近的“X-R-R”三联体识别磷酸基团头部。利用分子动力学（MD）模拟，我们进一步阐述了赖氨酸丰富的N-末端结构域如何协助TIPE 1有利地结合磷脂酰肌醇（PI）的机制。除小分子底物外，我们还通过GST pull-down分析和尺寸排阻色谱法鉴定了Gαi3作为TIPE 1的直接结合伴侣。关键残基突变和预测的复合物结构的分析表明，TIPE 1与Gαi3的结合模式可能是非典型的。总之，我们的发现缩小了TIPE 1在Gαi3相关和PI诱导信号通路中的位置。Sarma
As a member of the tumor necrosis factor-α-induced protein 8 (TNFAIP8/TIPE) family, TIPE1 has been found to be associated with many cellular signaling pathways in regulating apoptosis, autophagy, and tumorigenesis. However, the position of TIPE1 in the signaling network remains elusive. Here we present the crystal structure of zebrafish TIPE1 in complex with phosphatidylethanolamine (PE) at a resolution of 1.38 Å. By comparison with structures of other three TIPE family proteins, a universal phospholipid-binding mode was proposed. Namely, the hydrophobic cavity binds to fatty acid tails, while ‘X-R-R’ triad nearby the entrance of cavity recognizes the phosphate group head. Using molecular dynamics (MD) simulations, we further elaborated the mechanism of how the lysine-rich N-terminal domain assisting TIPE1 to favorably bind to phosphatidylinositol (PI). Beside small molecule substrate, we identified Gαi3 as a direct-binding partner of TIPE1 using GST pull-down assay and size-exclusion chromatography. Analyses of key-residue mutations and predicted complex structure revealed that the binding mode of TIPE1 to Gαi3 could be non-canonical. In summary, our findings narrowed down TIPE1’s position in Gαi3-related and PI-inducing signaling pathways.Communicated by Ramaswamy H. Sarma