CDO1 and infection: To examine whether Cdo1 mediates CYS metabolism to CSA and HTAU, and whether this limits the use of CYS for GSH synthesis, we deleted Cdo1 with CRISPR/Cas9, followed by infection with empty or Cre expressing adenovirus to generate Cdo1-deficient, isogenic Keap1WT and Keap1R554Q MEFs.