Wirschell Maureen, Yang Chun, Yang Pinfen, Fox Laura, Yanagisawa Haru-aki, Kamiya Ritsu, Witman George B, Porter Mary E, Sale Winfield S
Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Mol Biol Cell. 2009 Jul;20(13):3044-54. doi: 10.1091/mbc.e09-04-0276. Epub 2009 May 6.
Our goal is to understand the assembly and regulation of flagellar dyneins, particularly the Chlamydomonas inner arm dynein called I1 dynein. Here, we focus on the uncharacterized I1-dynein IC IC97. The IC97 gene encodes a novel IC without notable structural domains. IC97 shares homology with the murine lung adenoma susceptibility 1 (Las1) protein--a candidate tumor suppressor gene implicated in lung tumorigenesis. Multiple, independent biochemical assays determined that IC97 interacts with both alpha- and beta-tubulin subunits within the axoneme. I1-dynein assembly mutants suggest that IC97 interacts with both the IC138 and IC140 subunits within the I1-dynein motor complex and that IC97 is part of a regulatory complex that contains IC138. Microtubule sliding assays, using axonemes containing I1 dynein but devoid of IC97, show reduced microtubule sliding velocities that are not rescued by kinase inhibitors, revealing a critical role for IC97 in I1-dynein function and control of dynein-driven motility.
我们的目标是了解鞭毛动力蛋白的组装和调控，特别是衣藻内臂动力蛋白I1动力蛋白。在此，我们聚焦于未被表征的I1动力蛋白中间链IC97。IC97基因编码一种没有显著结构域的新型中间链。IC97与小鼠肺腺瘤易感性1（Las1）蛋白具有同源性，Las1蛋白是一种与肺肿瘤发生相关的候选肿瘤抑制基因。多项独立的生化分析确定，IC97与轴丝中的α-和β-微管蛋白亚基相互作用。I1动力蛋白组装突变体表明，IC97与I1动力蛋白马达复合体中的IC138和IC140亚基均相互作用，并且IC97是包含IC138的调控复合体的一部分。使用含有I1动力蛋白但缺乏IC97的轴丝进行的微管滑动分析显示，微管滑动速度降低，且激酶抑制剂无法挽救这种降低，这揭示了IC97在I1动力蛋白功能以及动力蛋白驱动的运动控制中的关键作用。
