Required for leukotriene biosynthesis by ALOX5 (5-lipoxygenase). Anchors ALOX5 to the membrane. Binds arachidonic acid, and could play an essential role in the transfer of arachidonic acid to ALOX5. Binds to MK-886, a compound that blocks the biosynthesis of leukotrienes (By similarity). Homotrimer. Interacts with LTC4S and ALOX5 (By similarity). The C-terminal part after residue 140 is mostly disordered. Belongs to the MAPEG family.