A dynein light intermediate chain, D1bLIC, is required for retrograde intraflagellar transport
A dynein light intermediate chain, D1bLIC, is required for retrograde intraflagellar transport
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DOI：
10.1091/mbc.e04-05-0377
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发表时间：
2004-10-01
影响因子：
3.3
通讯作者：
Witman, GB
中科院分区：
文献类型：
--
作者：
Hou, YQ;Pazour, GJ;Witman, GB
鞭毛内转运（IFT）是鞭毛组装过程中颗粒沿着鞭毛的双向运动。衣原体逆行IFT的发动机是细胞质动力蛋白1b，它包含动力蛋白重链DHC 1b和轻中间链（LIC）D1 bLIC。为了研究LIC在IFT中的可能作用，我们鉴定了d1 blic突变体。DHC 1b在突变体中减少，表明D1 bLIC对于稳定动力蛋白1b是重要的。突变体具有可变长度的鞭毛，积累IFT颗粒蛋白，指示逆行IFT的缺陷。有趣的是，剩余的DHC 1b通常分布在突变体鞭毛中，这强烈表明缺陷在于货物与逆行马达的结合，而不是马达活动本身。细胞生长和高尔基体的定位和形态是正常的突变体，表明D1 bLIC主要参与逆行IFT。与哺乳动物LIC一样，D1 bLIC在其N-末端有一个磷酸结合结构域（P-环）。为了研究这个保守结构域的功能，d1 blic突变体细胞转化与设计表达D1 bLIC蛋白与突变的P-环的构建体。该构建体将突变细胞拯救为野生型表型，表明D1 bLIC在IFT中的功能不依赖于其P环。
Intraflagellar transport (IFT), the bidirectional movement of particles along flagella, is essential for flagellar assembly. The motor for retrograde IFT in Chlamydomonas is cytoplasmic dynein 1b, which contains the dynein heavy chain DHC1b and the light intermediate chain (LIC) D1bLIC. To investigate a possible role for the LIC in IFT, we identified a d1blic mutant. DHC1b is reduced in the mutant, indicating that D1bLIC is important for stabilizing dynein 1b. The mutant has variable length flagella that accumulate IFT-particle proteins, indicative of a defect in retrograde IFT. Interestingly, the remaining DHC1b is normally distributed in the mutant flagella, strongly suggesting that the defect is in binding of cargo to the retrograde motor rather than in motor activity per se. Cell growth and Golgi apparatus localization and morphology are normal in the mutant, indicating that D1bLIC is involved mainly in retrograde IFT. Like mammalian LICs, D1bLIC has a phosphate-binding domain (P-loop) at its N-terminus. To investigate the function of this conserved domain, d1blic mutant cells were transformed with constructs designed to express D1bLIC proteins with mutated P-loops. The constructs rescued the mutant cells to a wild-type phenotype, indicating that the function of D1bLIC in IFT is independent of its P-loop.