E2E1, E2G1, E2J1, E2J2, and E2L3 interact with MuRF1 in the presence of telethonin (A) Telethonin does not interact with E2s. Y2H experiments were performed using telethonin as a bait to confirm that this protein cannot directly interact with the E2 enzymes used in this work. The empty vector and the vector containing the LT construct were used as negative controls against telethonin to estimate potential background level. Signals above ‘empty’ and ‘LT’ lanes were considered as positive. Colonies were plated on selective medium [‐LTH + Aureo + 3‐AT] (Experimental section) and monitored during 21 days. LT, Large‐T antigen; Tele, telethonin. (B) Telethonin expression level in yeast varies according to methionine (Met) concentration in the medium. BD‐Tele, fusion protein between the binding domain of GAL4 and telethonin; Tele, telethonin. (C) Densitometry analysis from the immunoblot presented in (B). (D) Yeast three‐hybrid (Y3H) experiments revealed E2E1, E2G1, E2J1, E2J2, and E2L3 as MuRF1 partners in the presence of telethonin. E2‐expressing yeasts were mated against strains expressing either MuRF1 alone or MuRF1 and telethonin. Colonies were plated on selective medium [‐LTH + Aureo + 3‐AT] containing 134 mM Met. Results were observed at day 6. Three to four independent transformation experiments were performed and 11 to 32 colonies were analyzed for each E2.