摘要：

Excerpt The N-end rule relates the in vivo half-life1 of a protein to the identity of its N-terminal residue (Varshavsky 1992). Similar but distinct versions of the N-end rule have been shown to operate in all organisms examined, from mammals to fungi and bacteria. I summarize the current understanding of the N-end rule pathway and describe some of the recent methods that utilize the N-end rule. Features of a protein that confer metabolic instability are called degradation signals, or degrons (Varshavsky 1991). The essential component of one degron, the first to be identified, is a destabilizing N-terminal residue of a protein (Bachmair et al. 1986). This signal is called the N-degron. The N-end rule (defined above) results from the existence of N-degrons containing different destabilizing residues (Varshavsky 1992). In eukaryotes, the N-degron comprises two determinants: a destabilizing N-terminal residue and an internal lysine (or lysines) of a substrate. The lysine residue...

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