Proton-linked monocarboxylate transporter that mediates creatine transport across the plasma membrane. Interacts with isoform 2 of BSG. Expressed in eye lens. Expressed in lens at P1 and P7 (PubMed:21778275). The expression levels are higher than in adult lens (PubMed:21778275). Detected in the basolateral membrane of the lens epithelium, with strong staining at equatorial epithelium, and in differentiating secondary fiber cells at P1 (at protein level) (PubMed:21778275). Belongs to the major facilitator superfamily. Monocarboxylate porter (TC 2.A.1.13) family.