ABCC1 (ATP-binding cassette subfamily C member 1) is a multidrug resistance protein that mediates ATP-dependent export of diverse substrates from cells. The protein functions as a transporter for glutathione conjugates, organic anions, and various xenobiotics including chemotherapeutic agents 1. Recent structural studies reveal that ABCC1 forms homodimers and recognizes substrates through a positively charged binding pocket 2. ABCC1 plays a critical role in cancer drug resistance by reducing intracellular drug accumulation, with elevated expression observed across multiple tumor types 13. The transporter exhibits unique regulatory functions, including export of cyclic GMP-AMP (cGAMP) which negatively regulates the cGAS-STING innate immune pathway 2. ABCC1 also mediates cAMP efflux in airway smooth muscle cells, influencing cellular relaxation and potentially asthma pathophysiology 4. In glioblastoma, high ABCC1 expression paradoxically sensitizes cells to ferroptosis while conferring temozolomide resistance 5. The gene is transcriptionally regulated by ΔNp63 in squamous cell carcinomas and shows therapeutic potential in lysosomal storage disorders like Tay-Sachs disease 67. These diverse functions establish ABCC1 as a key regulator of cellular homeostasis and drug resistance.