FIGURE 6.

Mutant CDC48 does not increase the stability of ER-sequestered ricin B chain. Protoplasts were transfected with vector alone (vector) or plasmids encoding RTB or RTA and, where indicated, co-transfected with plasmids encoding wtCDC48 or CDC48QQ. Following pulse-chase analysis as under “Experimental Procedures,” RTB and RTA were immunoprecipitated from combined cell and medium samples. Numbers at the margins of gels indicate molecular mass markers in kilodaltons. Graphs show densitometric quantification of the RTB or RTA IPs when expressed alone or co-expressed with wtCDC48 or CDC48QQ, expressed as percentages of the total RTB or RTA present at the end of the pulse, and are the average values from three independent experiments. Error bars indicate standard deviation.