FIG 9.

Activities of the CPs lacking the N terminus of α3 or α7. (A) In-gel assay for proteasome activity using native PAGE. Affinity-purified proteasomes using anti-Flag antibodies from each strain bearing Flag-tagged β4 (Pre1) were subjected to native PAGE, followed by in-gel proteasome activity analysis using Suc-LLVY-MCA in the presence or absence of 0.025% SDS. RP2CP, CPs with two RPs; RPCP, CPs with one RP; RP, the 19S regulatory particle. (B) Binding affinity of Fub1 to wild-type, α3ΔN, and α7ΔN CPs. Total lysates and immunoprecipitates (IP) of anti-Flag antibodies were subjected to SDS-PAGE and Western blot analysis using anti-Flag and anti-Fub1 antibodies. (C) Cadmium resistance in the Δα3, Δfub1, FUB1-overexpressed, α3ΔN, and α7ΔN cells. The indicated strains were serially diluted, spotted on YPGal plus 5 mg/liter CdCl₂, and cultured at 27°C for 4 days.