Lee V D, Huang B
Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037.
Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):11039-43. doi: 10.1073/pnas.90.23.11039.
Caltractin, a 20-kDa calcium-binding protein, was previously purified and cloned at the DNA level from the unicellular green alga Chlamydomonas. It is a structural component of the basal body complex, the major microtubule-organizing center in Chlamydomonas and the functional homolog of the centrosome in the animal cell. Here we report the characterization of a cDNA encoding a human caltractin that shares a high degree of amino acid identity (70%) with its algal counterpart. Caltractin was identified in both HeLa and BHK cells as a 21-kDa polypeptide specifically localized to the centrosome of interphase and mitotic cells. The high level of conservation in the amino acid sequence of caltractin from algae to humans and its association with the major microtubule-organizing center in the cell suggest that caltractin plays a fundamental role in microtubule-organizing center structure and function.
钙牵蛋白是一种20千道尔顿的钙结合蛋白，先前已从单细胞绿藻衣藻中纯化并在DNA水平上进行克隆。它是基体复合体的结构成分，是衣藻中主要的微管组织中心，也是动物细胞中心体的功能同源物。在此我们报告了一个编码人钙牵蛋白的cDNA的特性，该蛋白与其藻类对应物具有高度的氨基酸同一性（70%）。在HeLa细胞和BHK细胞中均鉴定出钙牵蛋白为一种21千道尔顿的多肽，特异性定位于间期细胞和有丝分裂细胞的中心体。从藻类到人类，钙牵蛋白氨基酸序列的高度保守性及其与细胞中主要微管组织中心的关联表明，钙牵蛋白在微管组织中心的结构和功能中发挥着重要作用。
