The ubiquitin codes in cellular stress responses

Ubiquitination/ubiquitylation,one of the most fundamental post-translational modifications,regulates almost every critical cellular process in eukaryotes.Emerging evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses,from exogenous factors to cellular reactions,causing a dazzling variety of functional consequences.Various forms of ubiquitin sig-nals generated by ubiquitylation events in specific milieus,known as ubiquitin codes,constitute an intrinsic part of myriad cellular stress responses.These ubiquitination events,leading to proteolytic turnover of the substrates or just switch in functionality,initiate,regulate,or supervise multiple cellular stress-associated responses,supporting adaptation,homeostasis recovery,and survival of the stressed cells.In this review,we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses,while discussing how stresses modulate the ubiquitin system.This review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.

Genome-wide pan-GPCR cell libraries accelerate drug discovery

G protein-coupled receptors(GPCRs)are pivotal in mediating diverse physiological and pathological processes,rendering them promising targets for drug discovery.GPCRs account for about 40%of FDA-approved drugs,representing the most successful drug targets.However,only approximately 15%of the 800 human GPCRs are targeted by market drugs,leaving numerous opportunities for drug discovery among the remaining receptors.Cell expression systems play crucial roles in the GPCR drug discovery field,including novel target identification,structural and functional characterization,potential ligand screening,signal pathway elucidation,and drug safety evaluation.Here,we discuss the principles,applications,and limitations of widely used cell expression systems in GPCR-targeted drug discovery,GPCR function investigation,signal pathway characterization,and pharmacological property studies.We also propose three strategies for constructing genome-wide pan-GPCR cell libraries,which will provide a powerful platform for GPCR ligand screening,and facilitate the study of GPCR mechanisms and drug safety evaluation,ultimately accelerating the process of GPCR-targeted drug discovery.

DNA bridging of FOXP3 ladder-like multimer: Unveiling a novel transcriptional regulation paradigm

In the latest issue of Nature,Zhang et al.characterized a novel ladder-like structure of FOXP3-DNA interaction involving FOXP3 multimerization and remote DNA bridging through a combination of biochemistry,structural biology,cell biology,and bioinformatics analyses.1 In this commentary,we highlight their key findings and provide our insights into the research paradigm for further exploration of a novel transcriptional regulation mode as well as a therapeutic strategy from the structural aspects of the FOXP3 complex(Figure 1).