Collins C A, Vallee R B
Cell Biology Group, Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts.
Cell Motil Cytoskeleton. 1989;14(4):491-500. doi: 10.1002/cm.970140407.
A microtubule associated protein from brain tissue (MAP 1C), has been found to possess many properties in common with ciliary and flagellar dyneins (Paschal et al.:J. Cell Biol. 105:1273-1282, 1987). However, this protein, now designated as cytoplasmic dynein, exhibited several properties which distinguish it from axonemal forms of the enzyme. We have investigated these characteristics further in a study of cytoplasmic dyneins from non-neuronal tissues. Rat liver and testis in particular were found to contain high levels of cytoplasmic dynein. The yield of dynein from testis was over 70 micrograms/g of tissue, making this the best source of cytoplasmic dynein of all tissues so far examined. The characterization of dynein from these sources has confirmed and extended our previous observations concerning the unique properties of cytoplasmic dynein. Activation of liver and testis dynein occurred at low (less than 1 mg/ml) tubulin concentration. Polypeptides identified as subunits of brain cytoplasmic dynein (74, 59, 57, 55, and 53 kDa) were present in liver and testis preparations. In addition, polypeptides at 150 and 45 kDa were found to copurify with the non-neuronal dyneins. The liver and testis enzyme hydrolyzed pyrimidine nucleotides at rates up to 12.5 times faster than ATP, though the relative affinity of cytoplasmic dynein for CTP was much lower (Km = 1.0 mM) than that for ATP. The properties of the testis enzyme were consistent with its identification as a cytoplasmic dynein rather than a sperm axonemal precursor. These data indicate that cytoplasmic dyneins may be widespread in distribution and that they share certain biochemical properties unique from those of axonemal dyneins. These characteristics are consistent with the proposal that cytoplasmic dynein plays a universal role in retrograde organelle motility.
已发现一种来自脑组织的微管相关蛋白（MAP 1C）具有许多与纤毛和鞭毛动力蛋白相同的特性（帕斯卡等人：《细胞生物学杂志》105:1273 - 1282，1987）。然而，这种现在被命名为胞质动力蛋白的蛋白质表现出了一些使其与轴丝形式的该酶相区别的特性。我们在一项对非神经组织胞质动力蛋白的研究中进一步探究了这些特征。特别发现大鼠肝脏和睾丸含有高水平的胞质动力蛋白。从睾丸中提取的动力蛋白产量超过70微克/克组织，使其成为迄今为止所检测的所有组织中胞质动力蛋白的最佳来源。对来自这些来源的动力蛋白的特性分析证实并扩展了我们之前关于胞质动力蛋白独特性质的观察结果。肝脏和睾丸动力蛋白在微管蛋白浓度较低（低于1毫克/毫升）时被激活。在肝脏和睾丸制剂中存在被鉴定为脑胞质动力蛋白亚基的多肽（74、59、57、55和53千道尔顿）。此外，发现150和45千道尔顿的多肽与非神经动力蛋白共纯化。肝脏和睾丸中的酶水解嘧啶核苷酸的速度比ATP快达12.5倍，不过胞质动力蛋白对CTP的相对亲和力（Km = 1.0毫摩尔）远低于对ATP的亲和力。睾丸酶的特性与其被鉴定为胞质动力蛋白而非精子轴丝前体一致。这些数据表明胞质动力蛋白可能分布广泛，并且它们具有某些与轴丝动力蛋白不同的独特生化特性。这些特征与胞质动力蛋白在细胞器逆行运动中起普遍作用的提议一致。
