Ezabella Teka | 2026 I.S. Symposium
Name: Ezabella Teka
Title: Exploring functional redundancy of glutaredoxins and thioredoxins in Saccharomyces Cerevisiae
Major: Biochemistry and Molecular Biology
Minor: Statistical and Data Sciences
笔补迟丑飞补测:听Public Health
Advisor: James West
The thioredoxin (Trx) and glutaredoxin (Grx) systems maintain redox balance in cells by reducing disulfide bonds in substrate proteins in an NADPH-dependent manner. Functional redundancy has been proposed between the two systems, since a single cytosolic Trx or Grx is required for viability in Saccharomyces cerevisiae. To explore this idea of Trx-Grx functional redundancy further, each Grx from S. cerevisiae was overexpressed in cells lacking the cytosolic Trx proteins Trx1 and Trx2. Unexpectedly, no Grxs could rescue the slow growth or peroxide sensitivity phenotypes in yeast lacking cytosolic Trx. These results suggest that Grx proteins may have distinct redox partners and functions. To identify potential redox partners of Grxs, a crosslinking approach using the bifunctional electrophile divinyl sulfone (DVSF) was employed. Seven of the eight glutaredoxins in yeast were identified as DVSF targets; Grx6 was not detected and could not be assessed. To determine which cysteine residues in the cytosolic glutaredoxins Grx1 and Grx2 were targeted by DVSF, Cys-to-Ala mutations were introduced at positions C27 and C30 in Grx1 and C61 and C64 in Grx2. Both active-site cysteines in Grx1 and Grx2 were confirmed to form crosslinks with DVSF. To determine whether the thioredoxin (Trx) and glutaredoxin (Grx) systems share interaction partners, a candidate-based approach was used in which epitope-tagged Grx1 and Grx2 were co-expressed with known thioredoxin substrates, including Tsa1, Tdh3, Rnr1, Srx1, and Ykg9. Protein interactions were captured using DVSF crosslinking followed by co-immunoprecipitation. These experiments identified potential shared redox partners of the glutaredoxin and thioredoxin systems, including Tsa1 and Ykg9.Future proteomic analyses will be important for more comprehensively defining the interactomes of cytosolic glutaredoxins and identifying additional proteins that may be regulated by both redox pathways.
Posted in Symposium 2026 on May 1, 2026.
