RPS3A encodes a structural component of the ribosomal small subunit, participating in ribosome biogenesis and protein synthesis. The protein localizes to the small-subunit processome and functions alongside ribosome biogenesis factors and RNA chaperones to facilitate pre-rRNA processing and cleavage. Beyond its canonical ribosomal role, RPS3A exhibits extraribosomal functions: it migrates to mitochondria to regulate brown adipocyte differentiation and function 1, and recent evidence suggests involvement in splicing and p53 regulation 2. In disease contexts, RPS3A levels are dysregulated in multiple conditions. In Alzheimer's disease, RPS3A is significantly upregulated specifically in brain capillaries alongside other ribosomal proteins and endoplasmic reticulum processing machinery 3. In coronary artery disease, RPS3A expression is decreased in epicardial adipose tissue, and knockdown impairs mitochondrial function, adipocyte browning, and accelerates vascular inflammation and atherosclerosis 1. RPS3A has emerged as an immune-cell-related biomarker in non-alcoholic fatty liver disease, with decreased hepatic expression correlating with disease progression 4. These findings position RPS3A not merely as a housekeeping ribosomal protein but as a metabolically and immunologically relevant factor in cardiovascular and metabolic disease.