Enables several functions, including folic acid binding activity; protein homodimerization activity; and thymidylate synthase activity. Involved in several processes, including nucleobase-containing small molecule metabolic process; response to steroid hormone; and response to vitamin. Located in mitochondrion and nucleolus. Used to study urinary bladder cancer. Biomarker of colorectal adenocarcinoma. Human ortholog(s) of this gene implicated in gastrointestinal system cancer (multiple); hematologic cancer (multiple); and rheumatoid arthritis. Orthologous to human TYMS (thymidylate synthetase). [provided by Alliance of Genome Resources, Apr 2022]