Phosphorylation of Ack1 by the Receptor Tyrosine Kinase Mer.
Phosphorylation of Ack1 by the Receptor Tyrosine Kinase Mer.
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DOI：
10.3390/kinasesphosphatases1030011
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发表时间：
2023-09
期刊：
影响因子：
--
通讯作者：
Miller, W Todd
中科院分区：
文献类型：
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作者：
Hayashi, Samantha Y;Craddock, Barbara P;Miller, W Todd
Ack 1是一种与细胞增殖和存活相关的非受体酪氨酸激酶。受体酪氨酸激酶Mer是TAM受体家族的一员，以前曾报道是Ack 1激酶的上游激活剂。然而，连接这两种激酶的机制尚未研究。我们通过免疫共沉淀实验证实了Ack 1和Mer相互作用，并发现Mer表达导致Ack 1活性增加。对Ack 1的影响依赖于Mer的激酶活性，而Mer C-末端酪氨酸Y867和Y 924的突变并没有显著降低Mer激活Ack 1的能力。Ack 1具有Mig 6同源区（MHR），其中包含相邻的调节性酪氨酸（Y859和Y860）。使用合成肽，我们表明，与pY 859序列相比，Mer优先结合并磷酸化含有磷酸化pY 860的MHR序列。这表明在MHR的Ack 1的顺序磷酸化的可能性，已经观察到以前的其他激酶。在共表达Mer和Ack 1 MHR突变体的细胞中，Y859 F突变体比Y860 F突变体具有更高的活性，与该模型一致。Mer和Ack 1之间的相互作用可能在正常生理学中的免疫细胞信号传导中发挥作用，也可能导致Ack 1在前列腺癌和其他肿瘤中的过度激活。
Ack1 is a nonreceptor tyrosine kinase that is associated with cellular proliferation and survival. The receptor tyrosine kinase Mer, a member of the TAM family of receptors, has previously been reported to be an upstream activator of Ack1 kinase. The mechanism linking the two kinases, however, has not been investigated. We confirmed that Ack1 and Mer interact by co-immunoprecipitation experiments and found that Mer expression led to increased Ack1 activity. The effect on Ack1 was dependent on the kinase activity of Mer, whereas mutation of the Mer C-terminal tyrosines Y867 and Y924 did not significantly decrease the ability of Mer to activate Ack1. Ack1 possesses a Mig6 Homology Region (MHR) that contains adjacent regulatory tyrosines (Y859 and Y860). Using synthetic peptides, we showed that Mer preferentially binds and phosphorylates the MHR sequence containing phosphorylated pY860, as compared to the pY859 sequence. This suggested the possibility of sequential phosphorylation within the MHR of Ack1, as has been observed previously for other kinases. In cells co-expressing Mer and Ack1 MHR mutants, the Y859F mutant had higher activity than the Y860F mutant, consistent with this model. The interaction between Mer and Ack1 could play a role in immune cell signaling in normal physiology and could also contribute to the hyperactivation of Ack1 in prostate cancer and other tumors.