Krendel Mira, Osterweil Emily K, Mooseker Mark S
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA.
FEBS Lett. 2007 Feb 20;581(4):644-50. doi: 10.1016/j.febslet.2007.01.021. Epub 2007 Jan 18.
Myosin 1E is one of two "long-tailed" human Class I myosins that contain an SH3 domain within the tail region. SH3 domains of yeast and amoeboid myosins I interact with activators of the Arp2/3 complex, an important regulator of actin polymerization. No binding partners for the SH3 domains of myosins I have been identified in higher eukaryotes. In the current study, we show that two proteins with prominent functions in endocytosis, synaptojanin-1 and dynamin, bind to the SH3 domain of human Myo1E. Myosin 1E co-localizes with clathrin- and dynamin-containing puncta at the plasma membrane and this co-localization requires an intact SH3 domain. Expression of Myo1E tail, which acts in a dominant-negative manner, inhibits endocytosis of transferrin. Our findings suggest that myosin 1E may contribute to receptor-mediated endocytosis.
肌球蛋白1E是两种“长尾”人类I类肌球蛋白之一，其尾部区域含有一个SH3结构域。酵母和变形虫肌球蛋白I的SH3结构域与Arp2/3复合物的激活剂相互作用，Arp2/3复合物是肌动蛋白聚合的重要调节因子。在高等真核生物中尚未鉴定出肌球蛋白I的SH3结构域的结合伴侣。在本研究中，我们发现两种在内吞作用中具有重要功能的蛋白质，即突触素-1和发动蛋白，与人类Myo1E的SH3结构域结合。肌球蛋白1E与质膜上含网格蛋白和发动蛋白的点状结构共定位，这种共定位需要完整的SH3结构域。以显性负性方式发挥作用的Myo1E尾部的表达抑制转铁蛋白的内吞作用。我们的研究结果表明，肌球蛋白1E可能有助于受体介导的内吞作用。
