Folate receptors, transporters, and folate-dependent enzymes (FOCM)

The folate receptors, transporters, and folate-dependent enzymes constitute a critical metabolic network responsible for the cellular uptake and utilization of folate (vitamin B9). Folate is a vital cofactor in one-carbon metabolism, which is essential for the synthesis of purines and thymidylate, and thus for DNA replication and repair (PubMed: 23115255). This system includes high-affinity folate receptors (e.g., Folate receptor alpha/FOLR1), transporters such as the Reduced folate carrier (SLC19A1) and Proton-coupled folate transporter (SLC46A1), and key enzymes like Dihydrofolate reductase (DHFR) and Thymidylate synthase (TYMS) (StatPearls: NBK541093). Because cancer cells exhibit an increased requirement for nucleotides to support rapid proliferation, many components of this pathway are overexpressed in tumors, particularly FOLR1 in ovarian and lung cancers (UniProt: P15328). Consequently, this system is a major focus for therapeutic intervention, ranging from classical antifolate chemotherapies like methotrexate to modern targeted therapies like antibody-drug conjugates (ADCs) (NCBI: PMC6163542). Beyond oncology, defects in folate transport or metabolism are associated with neural tube defects, megaloblastic anemia, and autoimmune conditions like rheumatoid arthritis (PubMed: 24529343).

Other names

Folate metabolic pathwayFolate transport systemFolate-mediated one-carbon metabolism proteinsVitamin B9 metabolic machinery

Inhibition of folate-dependent enzymes (DHFR, TYMS) to disrupt DNA synthesis; targeted delivery of cytotoxic agents via folate receptor-mediated endocytosis; competitive inhibition of folate transport mechanisms (PubMed: 23115255, NCBI: PMC6163542).