Supplementary Figure 1 Scmet15∆/Vector Scmet15∆/CgCYN1 Cystine Methionine Supplementary Figure.1. ORF CAGL0M00154g complements in S. cerevisiae for growth on cystine. Growth of S. cerevisiae met15∆ strain transformed with the vector control plasmid p416TEF (Scmet15∆/Vector) and with the C. glabrata ORF CAGL0M00154g (CgCYN1) under the TEF promoter in S. cerevisiae specific shuttle vector p416TEF (Scmet15∆/CgCYN1) on cystine (200µM) and methionine (200 µM). 1

Cgmet15 ∆cyn1∆/Vector Cgmet15 ∆cyn1∆/CgCYN1HA Cystine Methionine Cgmet15∆cyn1∆/Vector Cgmet15 ∆cyn1∆/CgCYN1HA Supplementary Figure 2 Supplementary Figure.2. CgCYN1 when tagged with a HA tag is functional. Growth of C. glabrata met15∆cyn1∆ strain transformed with CgCYN1 tagged with a HA tag in C. glabrata specific vector pGRB2.2 under PGK promoter (Cgmet15∆cyn1∆/CgCYN1HA) and with the corresponding vector control plasmid pGRB2.2 (Cgmet15∆cyn1∆/Vector) on cystine (200µM) and methionine (200 µM). 2

Cystine Methionine Scyct1∆met15 ∆/ CgCYN1 Scyct1∆met15 ∆/Vector Scyct1∆met15 ∆/Sp11.02 Supplementary Figure 3 A Scyct1∆met15 ∆/ CgCYN1 Scyct1∆met15 ∆/Vector Scyct1∆met15 ∆/Sp11.02 Supplementary Figure.3. A. S. pombe ORF SPCPB1C11.02 does not encode for a functional cystine transporter. A. Growth of S. cerevisiae met15∆ strain transformed with CgCYN1 (as positive control Scmet15∆/CgCYN1) and with S. pombe ORF SPCPB1C11.02 (Scmet15∆/Sp11.02) under TEF promoter in p416TEF plasmid and with the corresponding vector control plasmid p416TEF (Scmet15∆/Vector) on cystine (200µM) and methionine (200µM). 3

GSH Cysteine Amm. Cystine Cystine Methionine Sul. 200 μM 600μM Spcys1a∆ Supplementary Figure 3 B Supplementary Figure.3 B. Growth of S. pombe cys1a∆ strain on different sulphur sources like glutathione, cysteine ammonium sulphate, cystine (200µM and 600µM) and methionine. 4