The invention provides isolated nucleic acids molecules, designated 25466 nucleic acid molecules, which encode novel transporter molecules. The 25466 transporter molecules are homologous to monocarboxylate (MCT) transporters, and in particular to SLC16 family members. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing 25466 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a 25466 gene has been introduced or disrupted. The invention still further provides isolated 25466 proteins, fusion proteins, antigenic peptides and anti-25466 antibodies. Diagnostic and therapeutic methods utilizing compositions of the invention are also provided.