中文摘要：

为探讨蛋白激酶Sch9是否影响细胞蛋白质稳态水平及其在热胁迫时的响应,以野生型、SCH9基因缺失突变体、转sch9基因ΔSch9（SCH9-3HA）酵母为材料,利用特异的泛素抗体,检测长期培养时全蛋白泛素化水平变化.结果表明,Sch9缺失引起细胞全蛋白泛素化水平降低,转sch9基因可以使细胞全蛋白泛素化水平恢复.55℃热胁迫30 min处理,突变体Δsch9全蛋白泛素化水平降低,转sch9基因Δsch9（SCH9-3HA）全蛋白泛素化水平不变,回到正常生长温度时,蛋白泛素化水平也没有改变.外加蛋白酶体抑制剂MG132时,突变体ΔSch9蛋白泛素化水平不受影响,而转sch9基因△sch9（SCH9-3HA）全蛋白泛素化水平显著增加,表明前者是自噬途径降解,而增加部分是通过蛋白酶体途径降解.蛋白激酶Sch9调控细胞全蛋白泛素化水平,以及2个不同的降解途径.

英文摘要：

In yeast,Sch9 plays an important role on the regulation of lifespan and stress response.Meanwhile,the ubiquitinproteasome pathway and autophagy have an important role on the maintenance of protein homeostasis.In order to reveal the regulation of Sch9 on protein quality control,the variation of total ubiquitinated protein of wild-type yeast,Sch9 deleted yeast ΔSch9 and Sch9 deleted yeast that expressing HA-tagged ΔSch9（SCH9-3HA） were examined through a long term cultivation.The data demonstrated that Sch9 could regulate the ubiquitination of total protein.Because yeast could enhance cellular protection against thermal stress through the deletion of Sch9,a heat stress treatment at 55 ℃ for 30 min was applied to investigate the variation of ubquitination regulated by Sch9.The results indicated that Sch9 regulated the degradation of ubiquitinated protein under heat stress.In order to understand the regulation mechanism of the degradation of ubiquitinated protein by Sch9,ΔSch9 and ΔSch9（SCH9-3HA） were treated in the presence or absence of MG132.The results suggested that Sch9 could regulate the degradation of ubiquitinated protein through proteasome.