Intracellular proteolysis.

Our present understanding of intracellular protein degradation developed from an attempt to understand the metabolic stability of proteins in cells. With the unravelling of its complex biochemical machinery has come a realization that protein degradation plays an important role in the most crucial events in the cell cycle, in signal transduction and in maintaining the integrity of the proper folded state of proteins. In this review, I attempt to trace the curious history of intracellular protein degradation, its novel and elegant biochemistry and to extract the features that might be important for the next era of studies in cell physiology.