Luan Lin, Cao Xiaofu, Baskin Jeremy M
Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853.
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853.
bioRxiv. 2025 Jan 22:2025.01.21.634088. doi: 10.1101/2025.01.21.634088.
SQSTM1/p62 is a master regulator of the autophagic and ubiquitination pathways of protein degradation and the antioxidant response. p62 functions in these pathways via reversible assembly and sequestration of additional factors into cytoplasmic phase-separated structures termed p62 bodies. The physiological roles of p62 in these various pathways depends on numerous mechanisms for regulating p62 body formation and dynamics that are incompletely understood. Here, we identify a new mechanism for regulation of p62 oligomerization and incorporation into p62 bodies by SHKBP1, a Cullin-3 E3 ubiquitin ligase adaptor, that is independent of its potential functions in ubiquitination. We map a SHKBP1-p62 protein-protein interaction outside of p62 bodies that limits p62 assembly into p62 bodies and affects the antioxidant response by preventing sequestration and degradation of Keap1. These studies provide a non-ubiquitination-based mechanism for an E3 ligase adaptor in regulating p62 phase separation and cellular responses to oxidative stress.
SQSTM1/p62是蛋白质降解的自噬和泛素化途径以及抗氧化反应的主要调节因子。p62通过将其他因子可逆地组装并隔离到称为p62小体的细胞质相分离结构中，在这些途径中发挥作用。p62在这些不同途径中的生理作用取决于众多调节p62小体形成和动态变化的机制，而这些机制尚未完全明确。在此，我们确定了一种由Cullin-3 E3泛素连接酶接头SHKBP1调节p62寡聚化并并入p62小体的新机制，该机制独立于其在泛素化中的潜在功能。我们绘制了p62小体之外的SHKBP1-p62蛋白质-蛋白质相互作用图谱，该相互作用限制了p62组装进入p62小体，并通过阻止Keap1的隔离和降解来影响抗氧化反应。这些研究为E3连接酶接头在调节p62相分离和细胞对氧化应激反应中提供了一种基于非泛素化的机制。
