School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea.
Biochem Biophys Res Commun. 2024 Nov 12;733:150423. doi: 10.1016/j.bbrc.2024.150423. Epub 2024 Jul 18.
Autophagy and the ubiquitin-proteasome system (UPS) are two major protein quality control mechanisms maintaining cellular proteostasis. In Saccharomyces cerevisiae, the de novo synthesis of saturated fatty acids is performed by a multienzyme complex known as fatty acid synthase (FAS). A recent study reported that yeast FAS is preferentially degraded by autophagy under nitrogen starvation. In this study, we examined the fate of FAS during nitrogen starvation when autophagy is dysfunctional. We found that the UPS compensates for FAS degradation in the absence of autophagy. Additionally, we discovered that the UPS-dependent degradation of Fas2 requires the E3 ubiquitin ligase Ubr1. Our findings highlight the complementary relationship between autophagy and the UPS.
自噬和泛素-蛋白酶体系统（UPS）是维持细胞蛋白质稳态的两种主要蛋白质质量控制机制。在酿酒酵母中，从头合成饱和脂肪酸是由多酶复合物脂肪酸合酶（FAS）完成的。最近的一项研究报告称，在氮饥饿下，酵母 FAS 优先被自噬降解。在本研究中，当自噬功能失调时，我们研究了氮饥饿期间 FAS 的命运。我们发现，在没有自噬的情况下，UPS 补偿了 FAS 的降解。此外，我们发现 Fas2 的 UPS 依赖性降解需要 E3 泛素连接酶 Ubr1。我们的研究结果强调了自噬和 UPS 之间的互补关系。
