Transporter that mediates the import of cysteine into melanosomes, thereby regulating skin pigmentation (PubMed:33208952, PubMed:37751742). In melanosomes, cysteine import is required both for normal levels of cystine, the oxidized dimer of cysteine, and provide cysteine for the production of the cysteinyldopas used in pheomelanin synthesis, thereby regulating skin pigmentation (PubMed:33208952). Also catalyzes import of cysteine into lysosomes in non-pigmented cells, regulating lysosomal cystine and cysteine storage, which is essential for redox homeostasis (PubMed:33208952, PubMed:37751742). . This is the function of ENSG00000161091 (MFSD12, major facilitator superfamily domain containing 12).