Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada.
Division of Pulmonary and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado, USA.
FASEB J. 2018 Jun;32(6):3119-3132. doi: 10.1096/fj.201700966R. Epub 2018 Jan 22.
IL-1 signaling is adhesion-restricted in many cell types, but the mechanism that drives it is not defined. We screened for proteins recruited to nascent adhesions in IL-1-treated human fibroblasts with tandem mass tag-mass spectrometry. We used fibronectin bead preparations to enrich 10 actin-associated proteins. There was a 1.2 times log 2-fold enrichment of actin capping protein (ACP) at 30 min after IL-1 stimulation. Knockdown (KD) of ACP by siRNA reduced IL-1-induced ERK activation(by 56%, matrix metalloproteinase-3 (MMP-3) expression by 48%, and MMP-9 expression by 62% (in all reductions, P < 0.01). Confocal or structured illumination microscopy showed that ACP was diffused throughout the cytosol but strongly accumulated at the ruffled border of spreading cells. ACP colocalized with nascent paxillin- and vinculin-containing adhesions at the ruffled border, but not with mature adhesions in the center. ACP KD promoted the formation of large, stable adhesions. Immunoprecipitation and proximity ligation analysis showed that ACP was associated with the IL-1 signal transduction proteins myeloid differentiation factor 88 (MyD88) and IL-1 receptor-associated kinase (IRAK) at the ruffled border of the leading edge. IL-1-induced phospho-ERK and MyD88 or IRAK colocalized at the leading edge. We concluded that ACP is required for recruitment and function of IL-1 signaling complexes in nascent adhesions at the leading edge of the cell.-Wang, Q., Delcorde, J., Tang, T., Downey, G. P., McCulloch, C. A. Regulation of IL-1 signaling through control of focal adhesion assembly.
IL-1 信号在许多细胞类型中受到粘着限制，但驱动它的机制尚未确定。我们用串联质量标签-质谱法筛选了在白细胞介素-1 处理的人成纤维细胞中新生粘着处募集的蛋白质。我们用纤维连接蛋白珠制剂富集了 10 种与肌动蛋白相关的蛋白质。在白细胞介素-1 刺激后 30 分钟，肌动蛋白加帽蛋白（ACP）的富集程度为 1.2 倍对数 2 倍。通过 siRNA 敲低 ACP 可使白细胞介素-1 诱导的 ERK 激活减少 56%（基质金属蛋白酶-3（MMP-3）表达减少 48%，MMP-9 表达减少 62%（所有减少均为 P < 0.01）。共聚焦或结构照明显微镜显示，ACP 弥散在整个细胞质中，但在扩展细胞的皱襞边缘强烈积累。ACP 与新生的粘着斑蛋白（paxillin 和 vinculin）在皱襞边缘共定位，但不在中心的成熟粘着斑中。ACP 敲低促进了大而稳定的粘着斑的形成。免疫沉淀和邻近连接分析显示，ACP 与白细胞介素-1 信号转导蛋白髓样分化因子 88（MyD88）和白细胞介素-1 受体相关激酶（IRAK）在前沿的皱襞边缘相关。白细胞介素-1 诱导的磷酸化 ERK 和 MyD88 或 IRAK 在前沿处共定位。我们得出结论，ACP 是细胞前缘新生粘着处白细胞介素-1 信号复合物募集和功能所必需的。
