Proteins' N-termini contain information about their biochemical properties and functions, and they can undergo co- or post-translational modifications, as well as be processed by proteases. To expand the coverage of the N-terminome, we have developed LATE (LysN Amino Terminal Enrichment), a method that uses selective chemical derivatization of α-amines to isolate the N-terminal peptides. We applied LATE in combination with other N-terminomic method to study caspase-3 mediated proteolysis both in vitro and during apoptosis in cells. This enable us to identify many unreported caspase-3 cleavages, including some that cannot be identified by other methods. Furthermore, we find direct evidence that some of the caspase-3 generated neo-N-termini can be further modified by Nt-acetylation. This provides a global picture of the caspase-3 degradome and uncovers previously unrecognised functional crosstalk between post-translational Nt-acetylation and caspase proteolysis pathways.

No abstract

No abstract