PRAF2 (PRA1 domain family member 2) is a 19-kDa transmembrane protein with four membrane-spanning domains that functions in intracellular transport and vesicular trafficking. Primary function: PRAF2 is enriched in synaptic vesicles and participates in vesicle maturation, transport, and signal transmission in the brain 1. At the molecular level, PRAF2 acts as an ER-resident gatekeeper that retains G protein-coupled receptors (specifically GABAB receptor subunit GB1) in the endoplasmic reticulum, preventing premature biosynthetic progression 2. Mechanism: PRAF2 localizes to vesicle-like cytoplasmic structures and exists in monomeric and dimeric forms associated with different cellular compartments 3, suggesting functional compartmentalization. Disease relevance: PRAF2 expression is significantly elevated across multiple cancer types including neuroblastoma, glioma, colorectal cancer, hepatocellular carcinoma, and esophageal squamous cell carcinoma [PMID:23440329; 3; 4; 50]. High PRAF2 expression correlates with unfavorable prognostic features including MYCN amplification, metastasis, and poor overall survival [PMID:23440329; 65]. Clinical significance: PRAF2 knockdown reduces cellular proliferation, migration, invasion, and viability while inducing apoptosis [PMID:23440329; 3; 50], positioning PRAF2 as both a prognostic biomarker and potential therapeutic target in multiple malignancies.