Crucial role of the cGAS N terminus in mediating flowable and functional cGAS-DNA condensate formation via DNA interactions

• 成果类型: Article
• 署名作者: Jiang, Zhelin; Shi, Fan; Li, Juan; Liu, Rui; Zhou, Jinhua; Zhong, Zhensheng; Shi, Chaowei; Ma, Mingming; Xiang, Shengqi; Gao, Daxing
• 署名单位: Chinese Academy of Sciences; University of Science & Technology of China, CAS; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Anhui Medical University; Anhui Medical University; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Chinese Academy of Sciences; University of Science & Technology of China, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13616
• DOI: 10.1073/pnas.2411659122
• 发表日期: 2025-01-21
• 关键词: cyclic gmp-amp; phase-separation; binding; 2nd-messenger; synthase; PATHWAY; complex

摘要

The DNA- sensing protein cGAS plays a pivotal role in the innate immune response and pathogenesis of various diseases. DNA triggers liquid-liquid phase separation (LLPS) and enhances the enzymatic activity of cGAS. However, the regulatory mechanisms of the disordered N terminus remain unclear. Here, we showed that cGASNterm, the N- terminal intrinsic disordered region (IDR) of cGAS, modulates the material properties, specifically the flowability, of the condensed phase of cGAS and is required for full enzymatic activity. Full- length cGAS and cGASNterm form liquid droplets in the presence of DNA, while the cGAS catalytic domain forms gel- like solid aggregates with compromised enzymatic activity. Multiple key amino acids responsible for the cGASNterm-DNA interaction were identified by NMR spectroscopy as well as other biophysical methods and proven to be critical for the functional LLPS of cGAS both in vitro and in vivo. Interestingly, cGASNterm acts in trans to transform the solid aggregates of the cGAS catalytic domain into liquid droplets, subsequently restoring its enzymatic activity. Together, our findings highlight the importance of the IDR of cGAS in LLPS upon DNA stimulation and, more importantly, in modulating the fluidity and permeability of the droplets formed by full- length cGAS, which is crucial for its intact enzymatic activity.