Peripheral hyaline blebs (podosomes) of macrophages.
Peripheral hyaline blebs (podosomes) of macrophages.
复制标题
DOI：
10.1083/jcb.75.3.941
复制
发表时间：
1977-12
期刊：
影响因子：
--
通讯作者：
Stossel TP
中科院分区：
文献类型：
--
作者：
Davies WA;Stossel TP
质膜和透明外质共同构成巨噬细胞的感觉和运动器官。本研究的目的是分离该细胞组分，以便对其进行生化和功能分析。短暂的超声波加热兔肺巨噬细胞引起释放的异质性透明泡和丝状伪足，这是很容易收集的差速离心。在电子显微镜下观察，这些结构由主要含有肌动蛋白丝的膜结合囊组成。有些含有次级溶酶体。当它们来源于通过乳过氧化物酶催化反应用125（I）标记的细胞时，它们在特异性腺苷酸环化酶活性和三氯乙酸可沉淀的（125）I方面比全细胞匀浆富集三倍。这些标志物被发现具有相同的等密度密度时，巨噬细胞匀浆进行沉降在一个聚焦蔗糖密度梯度系统，这些标志物的密度不同于其他细胞质细胞器。因此，这些标志物被认为与巨噬细胞质膜相关。滤过泡组分的比β-葡萄糖醛酸酶活性与匀浆相似，但滤过泡的比琥珀酸脱氢酶活性和RNA含量明显较低，DNA检测不到。十二烷基硫酸钠聚丙烯酰胺凝胶上溶解的水泡的电泳显示与巨噬细胞肌动蛋白结合蛋白，肌球蛋白和肌动蛋白共迁移的多肽;水泡也有EDTA激活的腺苷三磷酸酶活性特征的肌球蛋白。肌动蛋白结合蛋白和肌球蛋白的浓度高于在细胞或细胞质提取物，而肌动蛋白浓度相似（相对于提取物）或仅略高于（比细胞）在水泡。在Triton X-100存在下，大疱和完整细胞具有高乳酸脱氢酶活性，但不存在。水泡和细胞氧化1-[（14）C]葡萄糖，并且在乳胶珠存在下葡萄糖氧化的速率显著增加。我们的结论是，完整的质膜囊包裹收缩蛋白和细胞质酶可以从巨噬细胞分离。它们富含肌球蛋白和肌动蛋白结合蛋白，表明收缩装置在细胞外周受到调节。这些结构有能力对环境信号作出反应。我们建议将它们命名为“podosomes”，因为它们与巨噬细胞伪足相似。我们提出，当膜处于积极扩展的构型时，足体形成是由于皮质凝胶的快速溶解。
The plasmalemma and hyaline ectoplasm together constitute the sensory and motor organ of macrophages. The purpose of this study was to isolate this cell fraction in order to analyze it biochemically and functionally. Brief sonification of warmed rabbit lung macrophages caused release of heterodisperse hyaline blebs and filopodia, which were easily collected by differential centrifugation. Viewed in the electron microscope, these structures consisted of membrane-bounded sacs principally containing actin filaments. Some contained secondary lysosomes. They were enriched threefold over whole cell homogenates in specific adenylate cyclase activity and in trichloroacetic-acid-precipitable (125)I when derived from cells labeled with 125(I) by means of a lactoperoxidase-catalyzed reaction. These markers were found to have identical isopycnic densitites when macrophage homogenates were subjected to sedimentation in a focusing sucrose density gradient system, and these markers had densities distinct from those of other cytoplasmic organelles. These markers were therefore assumed to be associated with macrophage plasma membranes. The specific β- glucuronidase activity of the bleb fraction was similar to that of homogenates, but the blebs had considerably lower specific succinic dehydrogenase activity and RNA content, and DNA was undetectable. Electrophoresis of blebs solubilized in sodium dodecyl sulfate on polyacrylamide gels revealed polypeptides co-migrating with macrophage actin-binding protein, myosin, and actin; blebs also had EDTA-activated adenosine triphosphatase activity characteristic of myosin. The concentrations of actin-binding protein and myosin were higher in blebs than in cells or cytoplasmic extracts, whereas actin concentrations were similar (relative to extracts) or only slightly greater (than in cells). Blebs and intact cells had high lactate dehydrogenase activities in the presence but not the absence of Triton X-100. Blebs and cells oxidased 1-[(14)C]glucose, and the rate of glucose oxidation was increased substantially in the presence of latex beads. We conclude that intact sacs of plasmalemma encasing contractile proteins and cytoplasmic enzymes can be isolated from macrophages. They are enriched in myosin and actin-binding protein, indicating that the contractile apparatus is regulated in the cell periphery. These structures have the capacity to respond to environmental signals. We suggest the name "podosomes" for them because of their resemblance to macrophage pseudopodia. We propose that podosome formation results from rapid dissolution of the cortical gel when the membrane is in an actively extended configuration.