Responsible for the transport of dicarboxylates such as succinate, fumarate, and malate from the periplasm across the inner membrane. Expression is maximal in early exponential growth phase and declines with cell density to reach a plateau in the stationary growth phase. Induced by the C(4)-dicarboxylates succinate, fumarate and malate. Positively regulated by RpoN and the DctB/DctD two-component system. Negatively autoregulated. Inactivation of the gene causes a growth defect in minimal media supplemented with succinate, fumarate or malate. The dctA-dctPQM double mutant shows no growth on malate and fumarate and residual growth on succinate. The DctPQM carrier is more efficient than the DctA carrier for the utilization of succinate at micromolar concentrations, whereas DctA is the major transporter at millimolar concentrations. Belongs to the dicarboxylate/amino acid:cation symporter (DAACS) (TC 2.A.23) family.