GROWTH-DEPENDENT CHANGE OF THE 26S PROTEASOME IN BUDDING YEAST

The 26S proteasome is assembled from the 20S proteasome and the regula tory subunit complex in an ATP-dependent manner. In the present study, we found that the ATP-dependent activity and the protein amount of th e 26S proteasome change during growth of the budding yeast Saccharomyc es cerevisiae. Both levels in the stationary phase are higher than tho se in the exponentially growing phase, On the other hand, the levels o f the 20S proteasome appear to remain unchanged during growth. These r esults suggest that the 26S proteasome undergoes a growth-dependent ch ange and that the 26S proteasome plays a role in the survival of yeast cells under starvation conditions. (C) 1998 Academic Press.