Fig. 1

Main aspects of folate receptor signaling and C1 metabolism discussed during the meeting. Three types of folate transporters/receptors are known to exist in humans to facilitate the uptake of folate: Folate Receptors (FRs), Reduced Folate Carrier (RFC) and Proton-Coupled Folate Transporter (PCFT) [57]. Left side: Folate binding to FRs can induce STAT3 activation via a GP130 co-receptor mediated JAK-dependent process. Folate can also bind FRs undergoing endocytosis and upon released FRs are set free to act like transcription factors [22]. Right side: Folate, through an interlinked set of mitochondrial and cytosolic reactions, support the C1 metabolism and the main pathway reactions are depicted [1, 6]. THF: tetrahydrofolate; MTHFR, methylenetetrahydrofolate reductase; SHMT1/2, serine hydroxymethyl transferase in cytosol (1) and mitochondrial (2); MTHFD1, methylenetetrahydrofolate dehydrogenase 1; MTHFD2, methylenetetrahydrofolate dehydrogenase 2; 10-f-THF: 10-formyl- tetrahydrofolate; GARFTase: glycinamide ribonucleotide formyltransferase; AICARFTase: 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase