Secretory Pathways Laboratory, London Research Institute, Cancer Research UK, London, UK.
EMBO J. 2012 Apr 18;31(8):1931-46. doi: 10.1038/emboj.2012.36. Epub 2012 Feb 21.
Autophagy is a catabolic process by which cytoplasmic components are sequestered and transported by autophagosomes to lysosomes for degradation, enabling recycling of these components and providing cells with amino acids during starvation. It is a highly regulated process and its deregulation contributes to multiple diseases. Despite its importance in cell homeostasis, autophagy is not fully understood. To find new proteins that modulate starvation-induced autophagy, we performed a genome-wide siRNA screen in a stable human cell line expressing GFP-LC3, the marker-protein for autophagosomes. Using stringent validation criteria, our screen identified nine novel autophagy regulators. Among the hits required for autophagosome formation are SCOC (short coiled-coil protein), a Golgi protein, which interacts with fasciculation and elongation protein zeta 1 (FEZ1), an ULK1-binding protein. SCOC forms a starvation-sensitive trimeric complex with UVRAG (UV radiation resistance associated gene) and FEZ1 and may regulate ULK1 and Beclin 1 complex activities. A second candidate WAC is required for starvation-induced autophagy but also acts as a potential negative regulator of the ubiquitin-proteasome system. The identification of these novel regulatory proteins with diverse functions in autophagy contributes towards a fuller understanding of autophagosome formation.
自噬是一种分解代谢过程，通过自噬体将细胞质成分隔离和运输到溶酶体进行降解，从而使这些成分得以循环利用，并在饥饿时为细胞提供氨基酸。它是一个高度调控的过程，其失调与多种疾病有关。尽管自噬在细胞内稳态中具有重要意义，但它并未被完全理解。为了寻找新的调节饥饿诱导自噬的蛋白质，我们在稳定表达 GFP-LC3 的人细胞系中进行了全基因组 siRNA 筛选，GFP-LC3 是自噬体的标记蛋白。使用严格的验证标准，我们的筛选鉴定了 9 种新的自噬调节剂。在自噬体形成所必需的命中蛋白中，有 SCOC（短卷曲螺旋蛋白），它是一种高尔基体蛋白，与成束延伸蛋白 zeta 1（FEZ1）相互作用，FEZ1 是 ULK1 结合蛋白。SCOC 与 UVRAG（紫外线辐射抗性相关基因）和 FEZ1 形成饥饿敏感的三聚体复合物，可能调节 ULK1 和 Beclin 1 复合物的活性。第二个候选蛋白 WAC 是饥饿诱导自噬所必需的，但也可能作为泛素-蛋白酶体系统的潜在负调节剂。这些具有不同自噬功能的新型调节蛋白的鉴定有助于更全面地理解自噬体的形成。
