SLC16A12 functions as a transporter for creatine and for its precursor, guanidinoacetate (GAA). Transport of both substrates is independent of resting membrane potential and of extracellular Na(+), Cl(-) or pH. The protein contributes to creatine biosynthesis and to the distribution of creatine between cells and tissues.

The SLC16A12 gene encodes a transmembrane protein that is found at the cell membrane, including the basolateral cell membrane. It belongs to the major facilitator superfamily and to the monocarboxylate porter family (TC 2.A.1.13), and HGNC places it in the solute carrier family 16 gene group. The NCBI Gene summary notes that it likely plays a role in monocarboxylic acid transport. Mouse and rat both carry an ortholog named Slc16a12.

The protein is known as monocarboxylate transporter 12 (MCT12) and as CRT2. Earlier HGNC names described it as a member of the solute carrier family 16 of monocarboxylic acid transporters. A mutation in the SLC16A12 gene has been associated with juvenile cataracts with microcornea and renal glucosuria, which makes the transporter of interest for studies of creatine handling, lens biology and renal transport.