RELL1 (RELT like 1) is a member of the RELT family of proteins that functions as a signaling mediator with dual roles in cell death and immune regulation. RELL1 induces activation of the p38 MAPK cascade when overexpressed, with this activation being more substantial than its homolog RELT and dependent on OSR1 and TRAF2 signaling molecules 1. The protein also induces apoptosis through overexpression, though the mechanism appears distinct from classical TNF receptor pathways 1. RELL1 localizes to the plasma membrane and physically interacts with RELT and RELL2 family members, forming functional complexes 2. In pathological contexts, RELL1 exhibits complex regulatory functions: it inhibits autophagy through direct mTOR interaction, promoting Mycobacterium tuberculosis survival in infected macrophages despite increased inflammatory cytokine production 3. Conversely, RELL1 expression is associated with poor prognosis in gliomas, functioning as an oncogene that accelerates tumor progression and influences immune cell infiltration 4. The protein is also involved in endothelial inflammation through circular RNA-mediated regulatory networks 5. These findings suggest RELL1 serves as a critical regulatory node balancing apoptosis, autophagy, and immune responses, with significant implications for infectious disease, cancer, and cardiovascular pathology.