Multiple unconventional myosin domains of the intestinal brush border cytoskeleton.
Multiple unconventional myosin domains of the intestinal brush border cytoskeleton.
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DOI：
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发表时间：
1994-12
影响因子：
4
通讯作者：
M. Heintzelman;T. Hasson;M. Mooseker
中科院分区：
文献类型：
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作者：
M. Heintzelman;T. Hasson;M. Mooseker
V类和VI类非常规肌球蛋白的代表被鉴定为肠刷状缘细胞骨架的组分。刷状缘肌球蛋白-I和肌球蛋白-II，这带来了四个肌球蛋白类与这一个亚细胞结构域，并表示在一个单一的后生动物细胞类型中表达的四类肌球蛋白的第一个表征。每种肌球蛋白的分布和细胞骨架结合是不同的，通过生化分离和免疫荧光定位进行评估。肌球蛋白-VI存在于微绒毛和终网，虽然终网是主要的集中地点。肌球蛋白-V存在于末端网中，最值得注意的是，在微绒毛的远端，从而成为第一个肌动蛋白结合蛋白定位到这个域，通过免疫组织化学和生物化学方法进行评估。在未分化的肠上皮细胞的肠隐窝，肌球蛋白-VI的表达，但尚未本地化的刷状缘，相反，肌球蛋白-V，这并不表明在这些细胞的顶端分布。肌球蛋白丰度的评估表明，虽然肌球蛋白-II是最丰富的细胞和刷状缘，刷状缘肌球蛋白-I只是略少丰富的肌球蛋白-V和-VI，这两个是两个数量级的丰富比别人少。提取研究表明，这四个肌球蛋白，肌球蛋白-V是最紧密的刷状缘膜，洗涤剂，除了ATP，需要有效的溶解。
Representatives of class V and class VI unconventional myosins are identified as components of the intestinal brush border cytoskeleton. With brush border myosin-I and myosin-II, this brings to four the number of myosin classes associated with this one subcellular domain and represents the first characterization of four classes of myosins expressed in a single metazoan cell type. The distribution and cytoskeletal association of each myosin is distinct as assessed by both biochemical fractionation and immunofluorescence localization. Myosin-VI exists in both the microvillus and terminal web although the terminal web is the predominant site of concentration. Myosin-V is present in the terminal web and, most notably, at the distal ends of the microvilli, thus becoming the first actin-binding protein to be localized to this domain as assessed by both immunohistochemical and biochemical methods. In the undifferentiated enterocytes of the intestinal crypts, myosin-VI is expressed but not yet localized to the brush border, in contrast to myosin-V, which does demonstrate an apical distribution in these cells. An assessment of myosin abundance indicates that while myosin-II is the most abundant in the cell and in the brush border, brush border myosin-I is only slightly less abundant in contrast to myosins-V and -VI, both of which are two orders of magnitude less abundant than the others. Extraction studies indicate that of these four myosins, myosin-V is the most tightly associated with the brush border membrane, as detergent, in addition to ATP, is required for efficient solubilization.