Large-scale Discovery of Substrates of the Human Kinome (MARK2) [Reanalysis: JPST000508]

Kinase -networks are important for cellular signal transduction. Despite tremendous efforts to uncover these signaling pathways, huge numbers of uncharacterized phosphosites still remain in the human proteome. Because of the transient nature of kinase-substrate interactions in vivo, it is almost impossible to identify direct substrates. Here, we present a novel strategy for the rapid and high-throughput discovery for of kinase substrates of kinase using quantitative proteomics. Using 385 purified kinases, we identified a total of 175,574 potential direct kinase substrates of kinases. In addition, we identified novel kinase groups, such as one group containing 30 threonine-directed kinases and another containing 15 serine/threonine/tyrosine kinase sgroup. Surprisingly, we observed that the diversity of substrates for tyrosine kinases was much higher than that for serine-threonine kinases. [Original project description]

激酶网络（kinase networks）在细胞信号转导过程中发挥关键作用。尽管学界已投入大量精力解析这类信号通路，人类蛋白质组中仍存在大量未被表征的磷酸化位点（phosphosites）。由于激酶-底物相互作用在体内具有瞬时性，直接鉴定激酶的天然直接底物几乎无法实现。本研究提出一种基于定量蛋白质组学（quantitative proteomics）的全新策略，可实现激酶底物的快速高通量发现。我们利用385种纯化激酶，共鉴定得到175574个潜在的激酶直接底物。此外，我们还发现了全新的激酶家族：例如包含30种苏氨酸定向激酶的家族，以及另一个由15种丝氨酸/苏氨酸/酪氨酸激酶组成的家族。令人意外的是，我们观测到酪氨酸激酶的底物多样性远高于丝氨酸-苏氨酸激酶。