ATP-dependent transporter of the ATP-binding cassette (ABC) family which transports various molecules including bioamines, neurotransmitters and metabolic intermediates (PubMed:812484, PubMed:18931318, PubMed:33820991). In the eye and probably in association with w/white, required for the transport of the eye brown pigment precursors, kynurenine and probably tryptophan, into pigment cell granules (PubMed:812484, PubMed:10407069). In Malpighian tubules and pupal eyes, involved in kynurenine transport (PubMed:812484). Probably in association with w/white, plays a role in zinc storage granule biogenesis in Malpighian tubule principal epithelial cells (PubMed:29367274). ATP + H2O + L-kynurenine(out) = ADP + H(+) + L-kynurenine(in) + phosphate May form a heterodimer with w/white. Co-localizes with w/white to pigment granules within pigment cells and retinula cells of the compound eye. Expressed in the eye, specifically in primary pigment cells, secondary pigment cells and retinula cells (at protein level). Expressed in early and late larvae, in pupae and, to a lesser extent, in adults. Eyes are scarlet due to a defect in brown pigment production (PubMed:10407069). In larval Malpighian tubules and pupal eyes, kynurenine uptake is impaired resulting in a severe decrease in 3-hydroxykynurenine production (PubMed:812484). In the head, levels of neurotransmitters histamine, dopamine and serotonin are reduced (PubMed:18931318). In addition, in lamina photoreceptor terminals R1-R6, numbers of synaptic vesicles and capitate projections, which are sites of endocytosis of vesicle membrane, are reduced (PubMed:18931318). Reduces the levels of several metabolites, including tryptophan, kynurenine, 3-hydroxykynurenine, guanosine, and, to a lesser extent, xanthine and riboflavin, and increases the levels of guanine and tetrahydrofolate (PubMed:33820991). 3-fold reduction in Malpighian tubule zinc stores (PubMed:29367274). Belongs to the ABC transporter superfamily. ABCG family. Eye pigment precursor importer (TC 3.A.1.204) subfamily.