Regulation of polymorphonuclear leukocyte phagocytosis by myosin light chain kinase after activation of mitogen-activated protein kinase
Regulation of polymorphonuclear leukocyte phagocytosis by myosin light chain kinase after activation of mitogen-activated protein kinase
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DOI：
10.1182/blood.v95.7.2407.007k02_2407_2412
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发表时间：
2000-04-01
期刊：
影响因子：
20.3
通讯作者：
Boxer, LA
中科院分区：
文献类型：
--
作者：
Mansfield, PJ;Shayman, JA;Boxer, LA
由Fc γ RII介导的多形核白细胞（PMNL）吞噬作用与促分裂原活化蛋白（MAP）激酶、细胞外信号调节激酶ERK 2的激活同步进行。我们假设肌球蛋白轻链激酶（MLCK）可以被磷酸化并被激活通过ERK，从而将MAP激酶途径与伪足形成所需的细胞骨架成分的激活联系起来。为了探索这种潜在的联系，用抗体包被的红细胞（EIgG）攻击PMNL。MLCK活性峰值比对照组增加3倍，发生在4至6分钟，与靶摄取和ERK 2活性的峰值速率相对应。MLCK抑制剂ML-7（10 μ mol/L）将吞噬作用和MLCK活性抑制至基础值，从而进一步支持功能反应与MLCK激活要求之间的联系。MAPK激酶（MEK）抑制剂PD 098059抑制吞噬作用、MLCK活性和ERK 2活性达80%至90%。为了将ERK活化与MLCK活化直接联系起来，在EIgG摄入后，从PMNL免疫沉淀ERK 2。将分离的ERK 2与作为未活化MLCK来源的PMNL胞质溶胶和MLCK底物孵育;在这些条件下，ERK 2活化MLCK，导致MLCK底物或肌球蛋白轻链本身磷酸化。由于MLCK激活肌球蛋白，我们评估了使用2，3-丁二酮单肟（BDM）直接抑制肌球蛋白腺苷三磷酸酶的效果，发现吞噬作用被抑制90%以上，但MLCK活性不受影响。这些结果与MEK激活ERK，ERK 2然后激活MLCK，MLCK激活肌球蛋白的解释一致，MLCK激活是导致伪足形成的细胞骨架变化中的关键步骤（Blood，2000;95：2407-2412）（C）2000，由美国血液学学会（The American Society of Hematology）提供。
Polymorphonuclear leukocyte (PMNL) phagocytosis mediated by Fc gamma RII proceeds in concert with activation of the mitogen-activated protein (MAP) kinase, extracellular signal-regulated kinase ERK2, We hypothesized that myosin light chain kinase (MLCK) could be phosphorylated and activated by ERK, thereby linking the MAP kinase pathway to the activation of cytoskeletal components required for pseudopod formation. To explore this potential linkage, PMNLs were challenged with antibody-coated erythrocytes (EIgG). Peak MLCK activity, 3-fold increased over controls, occurred at 4 to 6 minutes, corresponding with the peak rate of target ingestion and ERK2 activity. The MLCK inhibitor ML-7 (10 mu mol/L) inhibited both phagocytosis and MLCK activity to basal values, thereby providing further support for the linkage between the functional response and the requirement for MLCK activation. The MAPK kinase (MEK) inhibitor PD098059 inhibited phagocytosis, MLCK activity, and ERK2 activity by 80% to 90%, To directly link ERK activation to MLCK activation, ERK2 was immunoprecipitated from PMNLs after EIgG ingestion. The isolated ERK2 was incubated with PMNL cytosol as a source of unactivated MLCK and with MLCK substrate; under these conditions ERK2 activated MLCK, resulting in phosphorylation of the MLCK substrate or of the myosin light chain itself. Because MLCK activates myosin, we evaluated the effect of directly inhibiting myosin adenosine triphosphatase using 2,3-butanedione monoxime (BDM) and found that phagocytosis was inhibited by more than 90% but MLCK activity remained unaffected. These results are consistent with the interpretation that MEK activates ERK, ERK2 then activates MLCK, and MLCK activates myosin, MLCK activation is a critical step in the cytoskeletal changes resulting in pseudopod formation, (Blood, 2000;95:2407-2412) (C) 2000 by The American Society of Hematology.