Yasui Norihisa, Findlay Greg M, Gish Gerald D, Hsiung Marilyn S, Huang Jin, Tucholska Monika, Taylor Lorne, Smith Louis, Boldridge W Clifford, Koide Akiko, Pawson Tony, Koide Shohei
Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.
Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada.
Mol Cell. 2014 Jun 19;54(6):1034-1041. doi: 10.1016/j.molcel.2014.05.002. Epub 2014 Jun 5.
Cell signaling depends on dynamic protein-protein interaction (PPI) networks, often assembled through modular domains each interacting with multiple peptide motifs. This complexity raises a conceptual challenge, namely to define whether a particular cellular response requires assembly of the complete PPI network of interest or can be driven by a specific interaction. To address this issue, we designed variants of the Grb2 SH2 domain ("pY-clamps") whose specificity is highly biased toward a single phosphotyrosine (pY) motif among many potential pYXNX Grb2-binding sites. Surprisingly, directing Grb2 predominantly to a single pY site of the Ptpn11/Shp2 phosphatase, but not other sites tested, was sufficient for differentiation of the essential primitive endoderm lineage from embryonic stem cells. Our data suggest that discrete connections within complex PPI networks can underpin regulation of particular biological events. We propose that this directed wiring approach will be of general utility in functionally annotating specific PPIs.
细胞信号传导依赖于动态的蛋白质-蛋白质相互作用（PPI）网络，这些网络通常通过模块化结构域组装而成，每个结构域都与多个肽基序相互作用。这种复杂性带来了一个概念上的挑战，即确定特定的细胞反应是需要组装感兴趣的完整PPI网络，还是可以由特定的相互作用驱动。为了解决这个问题，我们设计了Grb2 SH2结构域的变体（“pY钳”），其特异性在许多潜在的pYXNX Grb2结合位点中高度偏向于单个磷酸酪氨酸（pY）基序。令人惊讶的是，将Grb2主要导向Ptpn11/Shp2磷酸酶的单个pY位点，而不是其他测试位点，就足以使胚胎干细胞分化出必需的原始内胚层谱系。我们的数据表明，复杂PPI网络中的离散连接可以支持特定生物学事件的调控。我们提出，这种定向布线方法在功能注释特定PPI方面将具有普遍实用性。
