Figure 1.

The folate and methionine metabolism in cytoplasm and mitochondria. Influx transporters are shown in green, efflux transporters in dark green, enzymes involved in glutamation in orange, cytoplasmic enzymes of the folate cycle in red, enzymes of the methionine cycle in blue, and mitochondrial enzymes of the folate cycle in purple. ATP Binding Cassette Subfamily C Member 1 (ABCC1), ATP Binding Cassette Subfamily C Member 3 (ABCC3), ATP Binding Cassette Subfamily B Member 1 (ABCB1), solute carrier family 19 member 1 (SLC19A1), solute carrier family 46 member 1 (SLC46A1), folate receptor α (FOLR1), folate receptor β (FOLR2), folate receptor γ (FOLR3), γ-glutamyl hydrolase (GGH), folate hydrolase 1 (FOLH1), folylpolyglutamate synthase (FPGS), dihydrofolate reductase (DHFR), methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1 (MTHFD1), aldehyde dehydrogenase 1 family member L1 (ALDH1L1), serine hydroxymethyltransferase 1 (SHMT1), methenyltetrahydrofolate synthetase (MTHFS), formimidoyltransferase cyclodeaminase (FTCD), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR), methylenetetrahydrofolate reductase (MTHFR), betaine-homocysteine S-methyltransferase (BHMT), betaine-homocysteine S-methyltransferase 2 (BHMT2), methionine adenosyltransferase 2A (MAT2A), glycine N-methyltransferase (GNMT), DNA methyltransferase 3 β (DNMT3B), adenosylhomocysteinase-like 1 (AHCYL1), cystathionine β-synthase (CBS), methylenetetrahydrofolate dehydrogenase 2, methenyltetrahydrofolate cyclohydrolase (MTHFD2), serine hydroxymethyltransferase 2 (SHMT2), methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L), aldehyde dehydrogenase 1 family member L2 (ALDH1L2), dihydrofolate (DHF), tetrahydrofolate (THF), S-adenosyl methionine (SAM), and S-adenosyl homocysteine (SAH), the dashed line represents the regeneration of MTR by MTRR.