Catalyzes the reversible phosphorylation of deoxythymidine monophosphate (dTMP) to deoxythymidine diphosphate (dTDP), using ATP as its preferred phosphoryl donor. Situated at the junction of both de novo and salvage pathways of deoxythymidine triphosphate (dTTP) synthesis, is essential for DNA synthesis and cellular growth (By similarity). ATP + dTMP = ADP + dTDP Pyrimidine metabolism; dTTP biosynthesis. Homodimer. The LID domain is a solvent-exposed domain that closes over the site of phosphoryl transfer upon ATP binding. Belongs to the thymidylate kinase family.