Analyzes of dynamic molecular organization of the membrane skeleton

1. 劳斯肉瘤病毒转化细胞的细胞/基质黏附结构：我们观察到劳斯肉瘤病毒转化细胞既在腹侧质膜中心区域发育足质体，又沿细胞外周发育外周黏附。池小体在几分钟的时间尺度上运动活跃，而周围粘连则很少运动。肌动蛋白（actin）、肌球蛋白（myosin）、caldesmon蛋白（caldesmon）和原肌球蛋白（tropomyosin）等收缩蛋白在足小体内富集，这可能是足小体活跃运动的原因。相比之下，蛋白质不会在外周粘连中积累，而在外周粘连中，整合素会被富集。这些发现表明，当细胞侵入组织时，这两种粘附结构可能参与不同的功能；首先，细胞通过外周黏附稳定地附着在组织上；其次，足质体通过活跃的运动和分泌蛋白酶侵入组织。脑膜联蛋白VI的靶蛋白：为了阐明膜联蛋白VI的更多作用，我们在大鼠脑内寻找与膜联蛋白VI相互作用的蛋白。膜联蛋白VI以Ca^<2+>和磷脂依赖的方式结合到15种蛋白质上。在这些蛋白中，约有5种蛋白富集于细胞骨架部分。其中一种蛋白质被鉴定为钙蛋白。Annexin VI与calspectin结合，抑制calspectin的F-actin交联活性。这些观察结果表明，膜联蛋白VI可能参与许多神经元功能，包括膜细胞骨架的Ca^<2+>依赖性调节。神经细胞的肌动蛋白、肌动蛋白结合蛋白和运动细胞/基质黏附结构：培养的神经元在神经突尖端具有高度运动的细胞/基质黏附结构，称为生长锥。生长锥内富含肌动蛋白丝、肌凝蛋白、caldesmon、原肌凝蛋白和凝胶蛋白，这可能是生长锥运动活跃和对Ca^<2+>敏感的原因。我们发现，培养的星形胶质细胞也在这一过程中形成了高度运动性的粘附结构，并将其称为粘附皱褶接触。褶边触点的运动与生长触点相似。在星形胶质细胞黏附体、生长锥和足质体中也有收缩蛋白和凝胶的积累。这些发现表明，收缩蛋白和凝胶可能是这些运动粘附活性运动的分子基础。少

1. Cell/substratum adhesive structures of Rous sarcoma virus transformed cells : We observed that Rous sarcoma virus transformed-cells developed both podosomes under the center area of ventral plasma membrane and peripheral adhesion along the cell periphery. Podosomes moved actively on a time scale of minutes, while peripheral adhesions scarecely moved. Contractlie proteins (actin, myosin, caldesmon and tropomyosin) were enriched within the podosomes, which may be responsible for the active movement of podosomes. By contrast, the proteins were not acumulated in peripheral adhesions, where integrins, alternatively, were enriched. These findings suggest that the two adhesive structures may participate in different functions when the cells invade into tissues ; firstly, the cells attach stably on the tissue via peripheral adhesions, and secondly, the podosomes invade into the tissue while activly moving and secreting proteases.2. Target proteins of annexin VI in brain : To elucidate the r … More oles of annexin VI, we searched proteins interacting with annexin VI in the rat brains. Annexin VI bound to 15 spieces of proteins in a Ca^<2+> and phospholipid dependent manner. Of these proteins, about 5 proteins were enriched in the cytoskeletal fraction. One of these proteins was identified to be calspectin. Annexin VI bound to calspectin, inhibiting the F-actin crosslinking activity of calspectin. These observations sugget that annexin VI may be involved in many neuronal functions including Ca^<2+>-dependent regulation of the membrane cytoskeleton.Actin and actin binding proteins, and motile cell/substratum adhesive structures of neural cells : Cultured neurons possess highly motile cell/substratum adhesive structures called growth cones at tips of neurites. Actin filaments, myosin, caldesmon, tropomyosin and gelsolin were enriched within the growth cones, which may be responsible for the active movement and Ca^<2+> sensitivity of growth cones. We found out that cultured astrocytes also developed highly motile adhesive structures along the processes and termed the adhesion ruffling contact. The movement of ruffling contact was similar to that of growth one. The contractile proteins and gelsolin were also accumulated in the adhesions of astrocytes as well as in growth cones and the podosomes. These findings show that the contratile protein and gelsolin may be molecular bases for the active movement of these motile adhesion. Less