Quantitative proteome analysis of the Arabidopsis thaliana N-degron pathway E3 ligase mutant, prt1-1.

The N-degron pathway relates the half-life of a protein to its amino terminal (Nt) residue. Following cleavage of proteins by endopeptidases, new N-t amino acids are revealed and can be recognised by different E3 ligase enzymes that target the substrate proteins for degradation via the proteasome. Studies with artificial proteins have shown that PRT1 is an Arabidopsis thaliana E3 ligase with specificity for aromatic N-termini (phenylalanine, tyrosine, tryptophan), but very little is known about its physiological roles and endogenous substrates. To gain insight into the impact of PRT1 on the proteome, we conducted a quantitative proteomic analysis, comparing leaf proteins from the prt1-1 loss of function mutant with those from wild type plants.