SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression

High KYNU Expression Is Associated with Poor Prognosis, KEAP1/STK11 Mutations, and Immunosuppressive Metabolism in Patient-Derived but Not Murine Lung Adenocarcinomas

Background/Objectives: We aimed to discover genes with bimodal expression linked to patient outcomes, to reveal underlying oncogenotypes and identify new therapeutic insights in lung adenocarcinoma (LUAD). Methods: We performed meta-analysis to screen LUAD datasets for prognostic genes with bimodal expression patterns. Kynureninase (KYNU), a key enzyme in tryptophan catabolism, emerged as a top candidate. We then examined its relationship with LUAD mutations, metabolic alterations, immune microenvironment states, and expression patterns in human and mouse models using bulk and single-cell transcriptomics, metabolomics, and preclinical model datasets. Pan-cancer prognostic associations were also assessed. Results: Model-based clustering of KYNU expression outperformed median-based dichotomization in prognostic accuracy. KYNU was elevated in tumors with KEAP1 and STK11 co-mutations but remained a strong independent prognostic marker. Metabolomic analysis showed that KYNU-high tumors had increased anthranilic acid, a catalytic product, while maintaining stable kynurenine levels, suggesting a compensatory mechanism sustaining immunosuppressive signaling. Single-cell and bulk data showed KYNU expression was cancer cell-intrinsic in immune-cold tumors and myeloid-derived in immune-infiltrated tumors. In murine LUAD models, Kynu expression was predominantly immune-derived and uncoupled from Nrf2/Lkb1 signaling, indicating poor model fidelity. KYNU's prognostic associations extended across cancer types, with poor outcomes in pancreatic and kidney cancers but favorable outcomes in melanoma, underscoring the need for lineage-specific considerations in therapy development. Conclusions:KYNU is a robust prognostic biomarker and potential immunometabolic target in LUAD, especially in STK11 and KEAP1 co-mutated tumors. Its cancer cell-intrinsic expression and immunosuppressive metabolic phenotype offer translational potential, though species-specific expression patterns pose challenges for preclinical modeling.

Selective phase separation of transcription factors is driven by orthogonal molecular grammar

Protein production is critically dependent on gene transcription rates, which are regulated by RNA polymerase and a large collection of different transcription factors (TFs). How these transcription factors selectively address different genes is only partially known. Recent discoveries show that the differential condensation of separate TF families through phase separation may contribute to selectivity. Here we address this by conducting phase separation studies on six TFs from three different TF families with residue-scale coarse-grained molecular dynamics simulations. Our exploration of ternary TF phase diagrams reveals four dominant sticker motifs and two orthogonal driving forces that dictate the resultant condensate morphology, pointing to sequence-dependent orthogonal molecular grammar as a generic molecular mechanism that drives selective transcriptional condensation in gene expression.

Pathological Involvement of Protein Phase Separation and Aggregation in Neurodegenerative Diseases

Neurodegenerative diseases are the leading cause of human disability and immensely reduce patients' life span and quality. The diseases are characterized by the functional loss of neuronal cells and share several common pathogenic mechanisms involving the malfunction, structural distortion, or aggregation of multiple key regulatory proteins. Cellular phase separation is the formation of biomolecular condensates that regulate numerous biological processes, including neuronal development and synaptic signaling transduction. Aberrant phase separation may cause protein aggregation that is a general phenomenon in the neuronal cells of patients suffering neurodegenerative diseases. In this review, we summarize the pathological causes of common neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, among others. We discuss the regulation of key amyloidogenic proteins with an emphasis of their aberrant phase separation and aggregation. We also introduce the approaches as potential therapeutic strategies to ameliorate neurodegenerative diseases through intervening protein aggregation. Overall, this review consolidates the research findings of phase separation and aggregation caused by misfolded proteins in a context of neurodegenerative diseases.