Sumoylation of Prdx6 made it less stable and affected its protective capacity. (A) hLECs were transfected with empty vector (lane 1) and pSumo-Star-Prdx6 construct (pMSumo-Star-vector, Life sensors) (lane, 2). 48h later, cell lysates were prepared from transfectants and resolved onto SDS-PAGE and immunoblotted with anti-Prdx6 antibody. Prdx6 protein showed cleaved protein bands (lane 2). (B) hLECs were transfected with pEGFP-vector (open bar), pMSumo-Star-Prdx6 (gray bar) or pGFP-Prdx6 (black bar) and exposed to H2O2 (100μM) for 24h before being subjected to MTS analysis. Results indicated significantly reduced viability in pMSumo-Star-Prdx6 (gray bar) transfected cells, while pGFP-Prdx6 (black bar) transfected cells were protected. Histogram values represent mean ± SD of three experiments (*p<0.001 vs control).