LAS24/KOG1, a component of the TOR complex 1 (TORC1), is needed for resistance to local anesthetic tetracaine and normal distribution of actin cytoskeleton in yeast
LAS24/KOG1, a component of the TOR complex 1 (TORC1), is needed for resistance to local anesthetic tetracaine and normal distribution of actin cytoskeleton in yeast
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DOI：
10.1266/ggs.80.325
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发表时间：
2005-10-01
影响因子：
1.1
通讯作者：
Toh-e, A
中科院分区：
文献类型：
--
作者：
Araki, T;Uesono, Y;Toh-e, A
众所周知，一些局部麻醉剂抑制出芽酵母细胞的生长。为了研究局部麻醉剂的作用途径，我们分离并鉴定了对丁卡因超敏感的突变体，同时对生长温度敏感。他们被统称为las（局部麻醉敏感）突变体。其中一个LAS基因LAS24被发现与KOG1相同，KOG1是独立发现的TOR复合体1 （TORC1）的成员。Las24p/Kog1p是一种广泛保守的TOR结合蛋白，含有NRC结构域、HEAT重复和WD-40重复，但其功能尚不清楚。与tor突变体一样，las24突变体被发现在细胞壁完整性上有缺陷，并且对雷帕霉素敏感。此外，Las24p不仅在翻译起始控制、Npr1p和Gln3p磷酸化等torc1介导的（雷帕霉素敏感）途径中是必需的，而且在肌动蛋白细胞骨架的正态分布中也是必需的，这被认为是torc2介导的事件。有趣的是，las24突变体的温度敏感性可以通过激活Tap42/pPase或下调RAS/cAMP途径来抑制。las24-1突变体的温度敏感性抑制因子对同一突变体的丁卡因敏感性抑制无效。这些观察结果以及丁卡因和高温对las24-1突变体的影响差异表明，Las24p/Kog1p不是丁卡因的靶标，丁卡因敏感步骤可能是TORC1途径的下游分支之一。与TOR通路发挥的广泛细胞功能一致，我们发现Las24p与膜相关，定位于液泡、质膜和小泡。
It is known that some local anesthetics inhibit the growth of budding yeast cells. To investigate the pathway of local anesthetics' action, we isolated and characterized mutants that were hyper-sensitive to tetracaine, and at the same time, temperature-sensitive for growth. They were collectively called las (local anesthetic sensitive) mutants. One of the LAS genes, LAS24, was found to be identical to KOG1, which had been independently discovered as a member of the TOR complex 1 (TORC1). Las24p/Kog1p is a widely conserved TOR binding protein containing the NRC domain, HEAT repeats and WD-40 repeats, but its function remains unknown. Like the tor mutants, the las24 mutants were found to have a defect in cell wall integrity and to show sensitivity to rapamycin. Furthermore, Las24p is required not only in TORC1-mediated (rapamycin-sensitive) pathways such as translation initiation control and phosphorylation of Npr1p and Gln3p, but also for the normal distribution of the actin cytoskeleton, which has been regarded as a TORC2-mediated event. Intriguingly, the temperature-sensitivity of the las24 mutant was suppressed by either activation of Tap42/pPase or by down-regulation of the RAS/cAMP pathway. Suppressors of the temperature-sensitivity of the las24-1 mutant were found not to be effective for suppression of the tetracaine-sensitivity of the same mutant. These observations along with the facts that tetracaine and high temperature differentially affected the las24-1 mutant suggest that Las24p/Kog1p is not a target of tetracaine and that the tetracaine-sensitive step may be one of downstream branches of the TORC1 pathway. Consistent with the broad cellular functions exerted by the TOR pathway, we found that Las24p was associated with membranes and was localized at vacuoles, the plasma membrane and small vesicles.