Cloning, localization, and axonemal function of Tetrahymena centrin
Cloning, localization, and axonemal function of Tetrahymena centrin
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DOI：
10.1091/mbc.e02-05-0298
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发表时间：
2003-01-01
影响因子：
3.3
通讯作者：
Satir, P
中科院分区：
文献类型：
--
作者：
Guerra, C;Wada, Y;Satir, P
Centrin 是一种 EF 手 Ca2+ 结合蛋白，已在嗜热四膜虫中克隆。它是一种 19.4 kDa 的 167 个氨基酸蛋白，具有独特的 N 末端区域，由包含 85 个碱基对内含子的单个基因编码。它与其他中心蛋白具有 > 80% 的同源性，与四膜虫 EF 手蛋白钙调蛋白、TCBP23 和 TCBP25 具有高度同源性。密切相关的四膜虫 EF 手蛋白的特定细胞定位与中心蛋白不同。 Centrin 定位于基底体、口腔器中的皮质纤维和睫状细根、顶端丝环以及沿着睫状轴丝的内臂 (14S) 动力蛋白 (IAD)。使用体外微管 (MT) 运动测定探索了中心蛋白在 Ca2+ 控制 IAD 活性中的功能。 Ca2+ 或模拟 Ca2+ 的肽 CALP1 在没有 Ca2+ 的情况下结合 EF 手蛋白，增加了 MT 滑动速度。中心蛋白抗体消除了这种增加。这是与轴丝动力蛋白相关的特定中心蛋白功能的首次演示。这表明中心蛋白是四膜虫轴丝 Ca2+ 反应（包括纤毛逆转或趋化性）的关键调节蛋白。
Centrin, an EF hand Ca2+ binding protein, has been cloned in Tetrahymena thermophila. It is a 167 amino acid protein of 19.4 kDa with a unique N-terminal region, coded by a single gene containing an 85-base pair intron. It has > 80% homology to other centrins and high homology to Tetrahymena EF hand proteins calmodulin, TCBP23, and TCBP25. Specific cellular localizations of the closely related Tetrahymena EF hand proteins are different from centrin. Centrin is localized to basal bodies, cortical fibers in oral apparatus and ciliary rootlets, the apical filament ring and to inner arm (14S) dynein (IAD) along the ciliary axoneme. The function of centrin in Ca2+ control of IAD activity was explored using in vitro microtubule (MT) motility assays. Ca2+ or the Ca2+-mimicking peptide CALP1, which binds EF hand proteins in the absence of Ca2+, increased MT sliding velocity. Antibodies to centrin abrogated this increase. This is the first demonstration of a specific centrin function associated with axonemal dynein. It suggests that centrin is a key regulatory protein for Tetrahymena axonemal Ca2+ responses, including ciliary reversal or chemotaxis.