Monocarboxylate transporter 3 (MCT3)

Monocarboxylate transporter 3 (MCT3), encoded by the SLC16A8 gene, is a proton-coupled transporter facilitating the rapid movement of monocarboxylates (such as lactate, pyruvate, and ketone bodies) across cell membranes[1][5]. MCT3 is selectively expressed in the basolateral membrane of the retinal pigment epithelium and in the choroid plexus, playing a critical role in regulating lactate and pH homeostasis in the retina[1][4][5]. Its function is essential for maintaining the proper metabolic environment required for photoreceptor activity and vision. MCT3, like other MCTs, operates as part of a heterodimeric complex with the glycoprotein CD147, which is necessary for correct plasma membrane localization and function[2][4]. Loss or dysfunction of MCT3—due to genetic deletion, injury, or disease—can result in impaired retinal metabolism and visual dysfunction, and has been linked to age-related macular degeneration and other RPE-related pathologies[5]. No specific approved drugs currently target MCT3, but drug development for other monocarboxylate transporters in the SLC16 family provides a model for potential future therapeutic targeting[6].

Other names

SLC16A8MCT3REMPsolute carrier family 16 member 8

For transporter inhibitors: competitively block substrate binding to the transporter, inhibiting lactate and proton flux (mechanism inferred from MCT1/4 inhibitors)