Involved in peptide utilization during carbon starvation. Induced by carbon starvation. Induction requires the cAMP-cAMP receptor protein (CRP) complex (PubMed:1848300). The carbon storage regulator CsrA regulates translation of cstA by sterically interfering with ribosome binding (PubMed:12867454). Belongs to the peptide transporter carbon starvation (CstA) (TC 2.A.114) family.