Membrane proximal ERK signaling is required for M-calpain activation downstream of epidermal growth factor receptor signaling
Membrane proximal ERK signaling is required for M-calpain activation downstream of epidermal growth factor receptor signaling
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DOI：
10.1074/jbc.m008847200
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发表时间：
2001-06-29
影响因子：
4.8
通讯作者：
Wells, A
中科院分区：
文献类型：
--
作者：
Glading, A;Überall, F;Wells, A
信号传导的定位在指导细胞结果中至关重要，特别是在多效性信号传导途径中。细胞外信号调节激酶（ERK）/微管相关蛋白激酶，促进细胞迁移，增殖和分化，发现在细胞核和整个细胞质。最近的研究表明，ERK的核转位是转录变化和细胞增殖所必需的。然而，胞质信号传导的细胞后果尚未确定。我们探讨了细胞质，特别是近膜，ERK信号是否参与生长因子诱导的细胞运动，我们以前已经证明，表皮生长因子受体（EGFR）介导的ERK激活下游的M-钙蛋白酶活性增加是必要的表皮生长因子（EGF）诱导的运动。钙蛋白酶同种型也已发现在核，胞质，和质膜相关的区室在各种细胞类型。我们现在采用细胞工程方法来控制上游EGFR和ERK活性的定位，以检查上游信号位置对下游钙蛋白酶活性的空间效应。与差异配体诱导的内化和交通限制受体的变体，我们发现，钙蛋白酶活性触发的质膜限制性激活的EGFR，而不是由内化（虽然仍然活跃）EGFR。细胞转染膜靶向ERK 1和ERK 2，螯合内源性ERK，表现出正常的EGF诱导的钙蛋白酶活性。转染一个无活性的ERK磷酸酶（MKP-3/Pyst 1），螯合ERK在细胞质中防止钙蛋白酶激活以及脱粘。这些数据有力地表明，EGF诱导的钙蛋白酶活性可以增强近膜EGFR介导的ERK信号传导的位点附近，提供有关钙蛋白酶活性如何调节和靶向增强其对粘附相关底物的影响的见解。
Localization of signaling is critical in directing cellular outcomes, especially in pleiotropic signaling pathways. The extracellular signal-regulated kinase (ERK)/ microtubule-associated protein kinase, which promotes cell migration, proliferation, and differentiation is found in the nucleus and throughout the cytoplasm. Recently, it has been shown that nuclear translocation of ERK is required for transcriptional changes and cell proliferation. However, the cellular consequences, of cytoplasmic signaling have not been defined. We explored whether cytoplasmic, specifically membrane-proximal, ERK signaling is involved in growth factor-induced cell motility, We previously have demonstrated that increased M-calpain activity downstream of epidermal growth factor receptor (EGFR)-mediated ERK activation is necessary for epidermal growth factor (EGF)induced motility. Calpain isoforms also have been found in nuclear, cytosolic, and plasma membrane-associated compartments in a variety of cell types. We now employ cell engineering approaches to control localization of the upstream EGFR and ERK activities to examine the spatial effect of upstream signal locale on downstream calpain activity. With differential ligand-induced internalization and trafficking-restricted receptor variants, we find that calpain activity is triggered only by plasma membrane-restricted activated EGFR, not by internalized (although still active) EGFR. Cells transfected with membrane-targeted ERK1 and ERK2, which sequester endogenous ERKs, exhibited normal EGF-induced calpain activity. Transfection of an inactive ERK phosphatase (MKP-3/Pyst1) that sequesters ERK in the cytoplasm prevented calpain activation as well as deadhesion. These data strongly suggest that EGF-induced calpain activity can be enhanced near sites of membrane-proximal EGFR-mediated ERK signaling, providing insights about how calpain activity might be regu lated and targeted to enhance its effects on adhesion-related substrates.