Noda Y, Sato-Yoshitake R, Kondo S, Nangaku M, Hirokawa N
Department of Anatomy and Cell Biology, Faculty of Medicine, University of Tokyo, Japan.
J Cell Biol. 1995 Apr;129(1):157-67. doi: 10.1083/jcb.129.1.157.
Kinesin is known as a representative cytoskeletal motor protein that is engaged in cell division and axonal transport. In addition to the mutant assay, recent advances using the PCR cloning technique have elucidated the existence of many kinds of kinesin-related proteins in yeast, Drosophila, and mice. We previously cloned five different members of kinesin superfamily proteins (KIFs) in mouse brain (Aizawa, H., Y. Sekine, R. Takemura, Z. Zhang, M. Nangaku, and N. Hirokawa. 1992. J. Cell Biol. 119:1287-1296) and demonstrated that one of them, KIF3A, is an anterograde motor (Kondo, S., R. Sato-Yashitake, Y. Noda, H. Aizawa, T. Nakata, Y. Matsuura, and N. Hirokawa. J. Cell Biol. 1994. 125:1095-1107). We have now characterized another axonal transport motor, KIF2. Different from other KIFs, KIF2 is a central type motor, since its motor domain is located in the center of the molecule. Recombinant KIF2 exists as a dimer with a bigger head and plus-end directionally moves microtubules at a velocity of 0.47 +/- 0.11 microns/s, which is two thirds that of kinesin's. Immunocytological examination showed that native KIF2 is abundant in developing axons and that it accumulates in the proximal region of the ligated nerves after a 20-h ligation. Soluble KIF2 exists without a light chain, and KIF2's associated-vesicles, immunoprecipitated by anti-KIF2 antibody, are different from those carried by existing motors such as kinesin and KIF3A. They are also distinct from synaptic vesicles, although KIF2 is accumulated in so-called synaptic vesicle fractions and embryonal growth cone particles. Our results strongly suggest that KIF2 functions as a new anterograde motor, being specialized for a particular group of membranous organelles involved in fast axonal transport.
驱动蛋白是一种典型的细胞骨架运动蛋白，参与细胞分裂和轴突运输。除了突变体分析外，最近利用聚合酶链反应（PCR）克隆技术取得的进展已阐明，在酵母、果蝇和小鼠中存在多种驱动蛋白相关蛋白。我们之前在小鼠脑中克隆了驱动蛋白超家族蛋白（KIFs）的五个不同成员（相泽浩、关根洋、竹村隆、张泽、南学、广川信隆。1992年。《细胞生物学杂志》119:1287 - 1296），并证明其中之一KIF3A是一种顺行运动蛋白（近藤慎、佐藤保武、野田洋、相泽浩、中田哲、松浦洋、广川信隆。《细胞生物学杂志》1994年。125:1095 - 1107）。我们现在已对另一种轴突运输运动蛋白KIF2进行了特性描述。与其他KIFs不同，KIF2是一种中央型运动蛋白，因为其运动结构域位于分子中心。重组KIF2以二聚体形式存在，头部较大，以0.47±0.11微米/秒的速度向正端方向移动微管，这是驱动蛋白速度的三分之二。免疫细胞化学检查表明，天然KIF2在发育中的轴突中含量丰富，并且在结扎20小时后积聚在结扎神经的近端区域。可溶性KIF2存在时没有轻链，用抗KIF2抗体免疫沉淀的KIF2相关囊泡与现有运动蛋白如驱动蛋白和KIF3A所携带的囊泡不同。它们也与突触囊泡不同，尽管KIF2积聚在所谓的突触囊泡组分和胚胎生长锥颗粒中。我们的结果有力地表明，KIF2作为一种新的顺行运动蛋白发挥作用，专门负责参与快速轴突运输的特定一组膜性细胞器的运输。
