Huang Zhifeng, Marsiglia William M, Basu Roy Upal, Rahimi Nader, Ilghari Dariush, Wang Huiyan, Chen Huaibin, Gai Weiming, Blais Steven, Neubert Thomas A, Mansukhani Alka, Traaseth Nathaniel J, Li Xiaokun, Mohammadi Moosa
School of Pharmacy, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China; Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.
Department of Chemistry, New York University, New York, NY 10012, USA.
Mol Cell. 2016 Jan 7;61(1):98-110. doi: 10.1016/j.molcel.2015.11.010. Epub 2015 Dec 10.
The molecular basis by which receptor tyrosine kinases (RTKs) recruit and phosphorylate Src Homology 2 (SH2) domain-containing substrates has remained elusive. We used X-ray crystallography, NMR spectroscopy, and cell-based assays to demonstrate that recruitment and phosphorylation of Phospholipase Cγ (PLCγ), a prototypical SH2 containing substrate, by FGF receptors (FGFR) entails formation of an allosteric 2:1 FGFR-PLCγ complex. We show that the engagement of pTyr-binding pocket of the cSH2 domain of PLCγ by the phosphorylated tail of an FGFR kinase induces a conformational change at the region past the cSH2 core domain encompassing Tyr-771 and Tyr-783 to facilitate the binding/phosphorylation of these tyrosines by another FGFR kinase in trans. Our data overturn the current paradigm that recruitment and phosphorylation of substrates are carried out by the same RTK monomer in cis and disclose an obligatory role for receptor dimerization in substrate phosphorylation in addition to its canonical role in kinase activation.
受体酪氨酸激酶（RTK）招募并磷酸化含Src同源2（SH2）结构域的底物的分子基础一直难以捉摸。我们使用X射线晶体学、核磁共振光谱和基于细胞的分析方法来证明，成纤维细胞生长因子受体（FGFR）对磷脂酶Cγ（PLCγ，一种典型的含SH2结构域的底物）的招募和磷酸化需要形成变构2:1 FGFR-PLCγ复合物。我们表明，FGFR激酶的磷酸化尾部与PLCγ的cSH2结构域的pTyr结合口袋结合，会在cSH2核心结构域之后包含Tyr-771和Tyr-783的区域诱导构象变化，以促进这些酪氨酸被另一个FGFR激酶反式结合/磷酸化。我们的数据推翻了目前认为底物的招募和磷酸化由同一RTK单体顺式进行的范式，并揭示了受体二聚化在底物磷酸化中的必要作用，此外它在激酶激活中还具有典型作用。
