G‐CSF‐dependent neutrophil differentiation requires downregulation of MAPK activities through the Gab2 signaling pathway
G‐CSF‐dependent neutrophil differentiation requires downregulation of MAPK activities through the Gab2 signaling pathway
复制标题
G-CSF依赖性中性粒细胞分化需要通过Gab2信号通路下调MAPK活性
DOI：
10.1002/cbin.11398
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发表时间：
2020
影响因子：
3.9
通讯作者：
Murakami Hiroshi
中科院分区：
文献类型：
--
作者：
Zhao Xianglin;Kawano Shun‐ichiro;Masuda Junko;Murakami Hiroshi
粒细胞集落刺激因子（G - CSF）刺激髓细胞诱导细胞蛋白酪氨酸磷酸化。其中一种酪氨酸磷酸化蛋白被发现是一种支架蛋白，Grb2相关结合蛋白2 （Gab2）。gabb家族蛋白的另一成员Gab3在中性粒细胞祖细胞中外源性过表达，使Gab3蛋白与内源性Gab2竞争G - CSF依赖性信号传导。在Gab3‐过表达的细胞中，G‐CSF刺激内源性Gab2的酪氨酸磷酸化水平明显下调，而Gab3的磷酸化水平显著增强。Gab3‐过表达的细胞在含有G‐CSF的培养基中持续增殖，并失去向成熟中性粒细胞分化的能力，其特征是分叶核。与亲本细胞相比，在G - CSF刺激后，Gab3的酪氨酸磷酸化依赖于G - CSF刺激，SHP2与Gab3的关联以及随后的丝裂原活化蛋白激酶（MAPK）激活在Gab3过表达的细胞中被延长，在亲本细胞中，SHP2与Gab2蛋白的结合以及MAPK的激活在G - CSF刺激后不持续。通过药物抑制剂抑制MAPK， Gab3‐过度表达的细胞恢复了向成熟中性粒细胞分化的能力。因此，G - CSF依赖性Gab2磷酸化和随后的下调导致了MAPK的短期激活。短暂的Gab2磷酸化后MAPK的下调对于G - CSF刺激诱导的中性粒细胞分化是必要的。
Granulocyte colony‐stimulating factor (G‐CSF) stimulation of myeloid cells induced tyrosine‐phosphorylation of cellular proteins. One of the tyrosine‐phosphorylated proteins was found to be a scaffold protein, Grb2‐associated binding protein 2 (Gab2). Another member of Gab family protein, Gab3, was exogenously overexpressed in neutrophil progenitor cells to make the Gab3 protein to compete with the endogenous Gab2 for the G‐CSF‐dependent signaling. In Gab3‐overexpressed cells, the level of tyrosine phosphorylation of endogenous Gab2 by G‐CSF stimulation was markedly downregulated, while the phosphorylation of Gab3 was significantly enhanced. The Gab3‐overexpressed cells continuously proliferated in the medium containing G‐CSF and lost the ability to differentiate to the mature neutrophil, characterized by the lobulated nucleus. The G‐CSF stimulation‐dependent tyrosine phosphorylation of Gab3, the association of SHP2 to Gab3 and the following mitogen‐activated protein kinase (MAPK) activation were prolonged in the Gab3‐overexpressed cells, compared to the parental cells, where the binding of SHP2 to Gab2 protein and thereby the activation of MAPK were not sustained after G‐CSF stimulation. Inhibition of MAPK by pharmaceutical inhibitor restored the Gab3‐overexpressed cells to the ability to differentiate to mature neutrophil. Therefore, G‐CSF‐dependent Gab2 phosphorylation and following its downregulation led the short‐term MAPK activation. The downregulation of MAPK after transient Gab2 phosphorylation was necessary for the consequent neutrophil differentiation induced by G‐CSF stimulation.