PPARGC1B (PGC-1β) is a transcriptional coactivator that serves as a master regulator of mitochondrial biogenesis and energy metabolism. It activates transcription factors including estrogen receptor alpha, nuclear respiratory factor 1 (NRF1), and glucocorticoid receptor [UniProt], and works downstream of nuclear receptors like RORγ and ERRα to coordinate oxidative phosphorylation (OXPHOS) programs 1. PPARGC1B overexpression increases basal oxygen consumption and mitochondrial number while promoting fat oxidation and energy expenditure regulation [UniProt]. At the molecular level, PPARGC1B functions through protein-binding interactions and mediator complex recruitment to positively regulate RNA polymerase II-dependent transcription and mitochondrial gene expression [GO annotations]. In disease contexts, PPARGC1B dysregulation contributes to cancer progression: RORγ-induced PGC-1β expression drives OXPHOS hyperactivation in osteosarcoma, supporting tumor growth 1, while PGC-1β degradation mediates sorafenib resistance in hepatocellular carcinoma by suppressing ROS and maintaining mitochondrial integrity 2. Conversely, IL-6-mediated suppression of PGC-1β expression impairs mitochondrial function during chr5 inflammation 3. Genetic variation at rs10071329 modulates PPARGC1B expression levels, with the G/G genotype enhancing expression and improving brown adipocyte mitochondrial respiration and lipolysis 4, suggesting clinical potential for precision medicine approaches targeting PPARGC1B in metabolic disorders.