PRRC1 (proline rich coiled-coil 1) is a cytosolic regulator of vesicular trafficking in the secretory pathway. Primary function: PRRC1 functions as an accessory factor essential for AP-4-mediated transport at the trans-Golgi network (TGN), operating independently of clathrin-dependent mechanisms 1. Mechanism: PRRC1 contains proline-rich domains and is recruited to endoplasmic reticulum (ER) exit sites where it interacts with the inner COPII coat to regulate anterograde trafficking 2. PRRC1 also interacts and colocalizes with MUC5AC in the Golgi, suggesting involvement in glycoprotein processing 3. Disease relevance: PRRC1 has been identified as a partner gene in MLL rearrangements associated with secondary acute lymphoblastic leukemia (sALL) following topoisomerase II inhibitor therapy 4. Additionally, PRRC1 shows significant association with fluid intelligence through genetic variation and gene methylation analysis 5. Clinical significance: Understanding PRRC1's role in vesicular trafficking and glycosylation may inform strategies targeting tumor progression pathways, particularly in lung adenocarcinoma where PRRC1-mediated MUC5AC modifications contribute to angiogenesis and metastasis 3.