Fig. 7.

The Rad23 shuttle factor fails to precipitate intact proteasomes from rpn3 mutants. (a) RPN3, rpn3-4, and rpn3-7 were transformed with a high-copy plasmid expressing FLAG-Rad23. An equal amount of protein extracts was prepared from cultures grown at either 23 °C or 37 °C and incubated with anti-FLAG Sepharose. The bound proteins were released in SDS-containing gel electrophoresis buffer and separated by SDS/PAGE. Immunoblots were incubated with antibodies to detect the proteasome subunits indicated on the left. (b) Protein levels detected in (a) were quantified by densitometry and plotted. [The lanes in (b) correspond to the same lanes in (a).]