Energy stress promotes P-bodies formation via lysine-63-linked polyubiquitination of HAX1

Energy stress, characterized by the reduction of intracellular ATP, has been implicated in various diseases, including cancer. Here, we show that energy stress promotes the formation of P-bodies in a ubiquitin-dependent manner. Upon ATP depletion, the E3 ubiquitin ligase TRIM23 catalyzes lysine-63 (K63)-linked polyubiquitination of HCLS1-associated protein X-1 (HAX1). HAX1 ubiquitination triggers its liquid‒liquid phase separation (LLPS) and contributes to P-bodies assembly induced by energy stress. Ubiquitinated HAX1 also interacts with the essential P-body proteins, DDX6 and LSM14A, promoting their condensation. Moreover, we find that this TRIM23/HAX1 pathway is critical for the inhibition of global protein synthesis under energy stress conditions. Furthermore, high HAX1 ubiquitination, and increased cytoplasmic localization of TRIM23 along with elevated HAX1 levels, promotes colorectal cancer (CRC)-cell proliferation and correlates with poor prognosis in CRC patients. Our data not only elucidate a ubiquitination-dependent LLPS mechanism in RNP granules induced by energy stress but also propose a promising target for CRC therapy. Synopsis Global translation inhibition is a hallmark of the cellular response to energy stress, but the underlying mechanism has not been fully elucidated. This study shows that energy stress promotes P-body formation in a TRIM23/HAX1-dependent manner to restrain protein synthesis. Energy stress enhances P-body formation through ubiquitination mediated by TRIM23. TRIM23 regulates HAX1 ubiquitination to support the LLPS of HAX1 and the condensation of LSM14A and DDX6. TRIM23/HAX1 is essential for the inhibition of global protein synthesis under energy stress conditions. The TRIM23/HAX1 pathway is critical for the tumorigenicity of colorectal cancer. Ubiquitination of HAX1 promotes the formation of P-bodies and is required for global translation downregulation during energy stress.