GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE326nnn/GSE326781/primaryOK200TranscriptomicsHomo sapiensExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE326781GEOGSEfalseBAG2 Condensates Couple Proteostasis to CD8 + T Cell SurveillanceProtein aggregation, impaired degradation, and immune activation are central hallmarks of many neurodegenerative diseases, yet how these processes are coordinated remain unclear. Here we identify a new class of phase-separated proteostasis organelles, termed immune degradation condensates (IDCs), composed of BAG2 assemblies. Inflammatory cues drive the formation of BAG2 IDCs, which are enriched in immunoproteasome components, major histocompatibility complex class I (MHC-I) peptide-loading machinery, and chaperones associated with the endoplasmic reticulum (ER). These assemblies redirect proteostatic cargo from centrosomal aggregation pathways to immune-specialized sites, coupling substrate clearance to antigenic peptide production and enhancing CD8⁺ T cell engagement. Using a cellular model of aggregation-prone Tau, we show that BAG2 IDCs capture pathological Tau fibrils at ER–microtubule interfaces and process them into antigenic peptides, thereby reducing the abundance of the aggregation-prone PHF6 motif. We term this system the Proteostasis-Associated Immune Relay (PAIR), establishing IDCs as critical hubs with potential implications for multiple disease states.2026/04/08GSE326781GSM9640472GSM9640471GSM9640474GSM9640473GSM9640470GSM9640469GSM9640468GSM9640476GSM9640475GSM9640467GSM9640477GSM964046618573326781Homo sapiens