Department of Cancer Biology, Dana-Farber Cancer Institute Boston, Boston, United States.
Department of Biological Chemistry & Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, United States.
Elife. 2021 Mar 23;10:e64251. doi: 10.7554/eLife.64251.
SHP2 is a protein tyrosine phosphatase that normally potentiates intracellular signaling by growth factors, antigen receptors, and some cytokines, yet is frequently mutated in human cancer. Here, we examine the role of SHP2 in the responses of breast cancer cells to EGF by monitoring phosphoproteome dynamics when SHP2 is allosterically inhibited by SHP099. The dynamics of phosphotyrosine abundance at more than 400 tyrosine residues reveal six distinct response signatures following SHP099 treatment and washout. Remarkably, in addition to newly identified substrate sites on proteins such as occludin, ARHGAP35, and PLCγ2, another class of sites shows reduced phosphotyrosine abundance upon SHP2 inhibition. Sites of decreased phospho-abundance are enriched on proteins with two nearby phosphotyrosine residues, which can be directly protected from dephosphorylation by the paired SH2 domains of SHP2 itself. These findings highlight the distinct roles of the scaffolding and catalytic activities of SHP2 in effecting a transmembrane signaling response.
SHP2 是一种蛋白酪氨酸磷酸酶，通常能增强生长因子、抗原受体和一些细胞因子的细胞内信号转导，但在人类癌症中经常发生突变。在这里，我们通过监测 SHP099 变构抑制 SHP2 时的磷酸肽组动力学，研究了 SHP2 在乳腺癌细胞对 EGF 反应中的作用。超过 400 个酪氨酸残基的磷酸酪氨酸丰度动力学显示，SHP099 处理和洗脱后有六种不同的反应特征。值得注意的是，除了在封闭蛋白、ARHGAP35 和 PLCγ2 等蛋白上新发现的底物位点外，另一类位点在 SHP2 抑制时显示出磷酸酪氨酸丰度降低。磷酸化减少的位点在附近有两个磷酸酪氨酸残基的蛋白质上富集，这些残基可以直接受到 SHP2 自身配对 SH2 结构域的保护而免于去磷酸化。这些发现强调了 SHP2 的支架和催化活性在产生跨膜信号反应中的不同作用。
