Docking sites on substrate proteins direct extracellular signal-regulated kinase to phosphorylate specific residues
Docking sites on substrate proteins direct extracellular signal-regulated kinase to phosphorylate specific residues
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DOI：
10.1074/jbc.m102512200
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发表时间：
2001-07-20
影响因子：
4.8
通讯作者：
Kornfeld, K
中科院分区：
文献类型：
--
作者：
Fantz, DA;Jacobs, D;Kornfeld, K
有丝分裂原活化蛋白激酶（Mitogen-activated protein kinase，MAP）如细胞外信号调节激酶（extracellular signal-regulated kinase，ERK）是重要的信号蛋白，可磷酸化许多不同蛋白底物中的（S/T）P位点，ERK与底物蛋白的结合是通过包括FXFP基序和D-结构域的对接位点介导的。在位置1和3处的苯丙氨酸的取代具有显著的效果，表明这些苯丙氨酸提供实质性的结合亲和力，而在位置2和4处的残基的取代具有较小的效果。FXFP和D-结构域对接位点在蛋白质ELK-1和KSR-1中的各种位置和排列进行了分析，我们的结果表明FXFP和D-结构域对接位点形成了具有两种功能的灵活的模块化系统。首先，底物对ERK的亲和力可以通过对接位点的数量、类型、位置和排列来调节。第二，在具有多个潜在磷酸化位点的底物中，对接位点可以指导特定（SPT）P残基的磷酸化。特别是，ELK-1的CDFP基序对于指导丝氨酸383的磷酸化是必要的和足够的，而D结构域指导ELK-1中其他（SPT）P位点的磷酸化。
Mitogen-activated protein (MAP) kinases such as extracellular signal-regulated kinase (ERK) are important signaling proteins that phosphorylate (S/T)P sites in many different protein substrates, ERK binding to substrate proteins is mediated by docking sites including the FXFP motif and the D-domain, We characterized the sequence of amino acids that can constitute the FXFP motif using peptide and protein substrates, Substitutions of the phenylalanines at positions 1 and 3 had significant effects, indicating that these phenylalanines provide substantial binding affinity, whereas substitutions of the residues at positions 2 and 4 had less effect. The FXFP and D-domain docking sites were analyzed in a variety of positions and arrangements in the proteins ELK-1 and KSR-1, Our results indicate that the FXFP and D-domain docking sites form a flexible, modular system that has two functions. First, the affinity of a substrate for ERK can be regulated by the number, type, position, and arrangement of docking sites. Second, in substrates with multiple potential phosphorylation sites, docking sites can direct phosphorylation of specific (SPT)P residues. In particular, the FQFP motif of ELK-1 is necessary and sufficient to direct phosphorylation of serine 383, whereas the D-domain directs phosphorylation of other (SPT)P sites in ELK-1.