SpOPT1, a member of the oligopeptide family (OPT) of the fission yeast Schizosaccharomyces pombe, is involved in the transport of glutathione through the outer membrane of the cell.

A protein involved in the transport of glutathione has been identified, cloned and characterized from the fission yeast Schizosaccharomyces pombe. Database searches revealed the Sz. pombe ORF SPAC29B12.10c as a close homologue to several members of the OPT family, including the Saccharomyces cerevisiae high-affinity glutathione transporter Hgt1p. The gene product of SPAC29B12.10c has been identified as a protein, named SpOPT1, localized within the plasma membrane, transporting the tripeptide glutathione. Disruption of SPAC29B12.10c led to strains inable to grow on media containing glutathione as a sole source of sulphur, due to the inability to internalize the tripeptide. Disruptants contained significantly less glutathione than wild-type cells. Furthermore, DeltaSpopt1 strains were non-viable in a glutathione biosynthesis-defective (Deltagsh2) background. However, it was possible to complement the disruption of Spopt1 by overexpressing the intact ORF in the disrupted strain.