HYOU1 (hypoxia up-regulated 1) is a molecular chaperone protein that plays critical roles in cellular stress responses and protein folding. Under hypoxic conditions and endoplasmic reticulum stress, HYOU1 promotes HSPA5/BiP-mediated ATP nucleotide exchange, thereby activating the unfolded protein response (UPR) pathway 1. The protein demonstrates significant clinical relevance across multiple pathological contexts. In cancer biology, HYOU1 functions as an oncogene, promoting cell proliferation, migration, and invasion through activation of PI3K/AKT signaling pathways in bladder cancer 2 and epithelial ovarian cancer 3. In papillary thyroid cancer, HYOU1 facilitates glycolysis by stabilizing LDHB mRNA expression 4. Beyond cancer, HYOU1 has emerged as a potential therapeutic target, with beneficial effects observed in heart disease prevention during caloric restriction 5. The gene shows disease associations with primary immunodeficiencies, as novel mutations in HYOU1 have been identified in patients with severe congenital neutropenia 6. Additionally, HYOU1 supports immune regulation by enhancing regulatory T cell function through mitochondrial N-glycosylation processes 1, highlighting its multifaceted role in both pathological and protective cellular mechanisms.