Intracellular proteolysis (Reprinted from Trends in Biochemical Science, vol 12, Dec., 1999)

Our present understanding of intracellular protein degradation developed fr om an attempt to understand the metabolic stability of proteins in cells. W ith the unravelling of its complex biochemical machinery has come a realiza tion that protein degradation plays an important role in the most crucial e vents in the cell cycle, in signal transduction and in maintaining the inte grity of the proper folded state of proteins. In this review, I attempt to trace the curious history of intracellular protein degradation, its novel a nd elegant biochemistry and to extract the features that might be important for the next era of studies in cell physiology.