Glenney J R, Weber K
Proc Natl Acad Sci U S A. 1981 May;78(5):2810-4. doi: 10.1073/pnas.78.5.2810.
Villin is a major F-actin-bundling protein present in the microfilament bundle underlying the plasma membrane of the microvilli present on intestinal epithelial cells. Mild in vitro proteolysis converts villin (Mr, 95,000) into a large fragment, the villin core (apparent Mr, 90,000). Villin core has lost the F-actin-bundling activity expressed by villin in the absence of calcium but retains the micromolar Kd calcium-binding site and the calcium-dependent restriction of actin filament length (F-actin severing) of intact villin. This finding suggests a common structural and functional relatedness between the known calcium-dependent F-actin-severing proteins from different cell types, even though not all of them reveal F-actin-bundling activity.
绒毛蛋白是一种主要的F-肌动蛋白成束蛋白，存在于肠道上皮细胞微绒毛质膜下的微丝束中。温和的体外蛋白水解作用将绒毛蛋白（分子量95,000）转化为一个大片段，即绒毛蛋白核心（表观分子量90,000）。绒毛蛋白核心在无钙条件下失去了绒毛蛋白所表现出的F-肌动蛋白成束活性，但保留了微摩尔解离常数的钙结合位点以及完整绒毛蛋白的肌动蛋白丝长度的钙依赖性限制（F-肌动蛋白切断）。这一发现表明，来自不同细胞类型的已知钙依赖性F-肌动蛋白切断蛋白之间存在共同的结构和功能相关性，尽管并非所有这些蛋白都显示出F-肌动蛋白成束活性。
