MCT4

Monocarboxylate transporter 4 (MCT4) also known as solute carrier family 16 member 3 (SLC16A3). MCT4 acts as an H+/lactate exporter in highly glycolytic tissues. In fact, MCT4 was first identified as a key component of lactate efflux in highly glycolytic white fiber myocytes, and was later demonstrated to show a high affinity for lactate over other monocarboxylates, as referenced by its comparatively lower Km for lactate. Furthermore, MCT4 has been shown to be overexpressed in diverse types of neoplasia, among malignant gliomas. Mechanistically, MCT4 is upregulated under hypoxia via binding of HIF-1α to two hypoxic response elements (HRE) within the SLC16A3 promoter. This process enables tumor cells, including those within the core of the heterogeneous tumor mass to survive, despite being at a distance from blood vessels that supply their metabolic needs.