Involved in L-cystine import (PubMed:25139244, PubMed:25837721, PubMed:26350134, PubMed:27481704). Low affinity L-cystine transporter that is mainly involved in L-cystine uptake from outside as a nutrient (PubMed:25837721). Is the primary transporter at high concentrations of cystine (PubMed:26350134). Probably functions as a proton symporter (Probable). Can also transport D-cystine, cysteine and homocystine as a methionine precursor (PubMed:25139244, PubMed:26350134). Mediates accumulation of the toxic compounds L-selenaproline (SCA) and L-selenocystine (SeCys) (PubMed:25139244). Can also transport S-sulfocysteine and is required for growth on S-sulfocysteine as a sulfur source (PubMed:27481704). Plays the principal role in the 3-mercaptopyruvate sulfurtransferase (3MST)-mediated generation of endogenous hydrogen sulfide (H2S) (PubMed:28533366). H(+)(out) + L-cystine(out) = H(+)(in) + L-cystine(in) Inhibited by L-cystine and L-cysteine, and to a lesser extent by D-cystine. Transcription is controlled by CysB (PubMed:26350134, PubMed:27481704, PubMed:28533366). Highly expressed in sulfate medium and repressed in cystine medium (PubMed:26350134). Disruption of the gene decreases uptake of cystine (PubMed:25837721). The mutant cannot grow on S-sulfocysteine (PubMed:27481704). The tcyP-tcyJ double mutant is unable to import cystine (PubMed:26350134, PubMed:27481704). The tcyP-tcyL double mutant cannot grow in the minimal medium containing L-cystine as a sole sulfur source (PubMed:25837721). The tcyP-tcyJ and tcyP-tcyL double mutants are completely resistant to both L-selenaproline and L-selenocystine (PubMed:25139244). Belongs to the dicarboxylate/amino acid:cation symporter (DAACS) (TC 2.A.23) family.