Peroxisome targeting signal 1: Is it really a simple tripeptide?

Originally.. the peroxisomal targeting signal 1 (PTS 1) was defined as a tripeptide at the C-terminus of proteins prone to be imported into the peroxisomal matrix. The corresponding receptor PEX5 initiates the translocation of proteins by identifying potential substrates via their C-termini and trapping PTS Is through remodeling of its TPR domain. Thorough studies on the interaction between PEX5 and PTS I as well as sequence-analytic tools revealed the influence of amino acid residues further upstream of the ultimate tripeptide. Altogether, PTS Is should be defined as dodecamer sequences at the C-terminal ends of proteins. These sequences accommodate physical contacts with both the surface and the binding cavity of PEX5 and ensure accessibility of the extreme C-terminus. Knowledge-based approaches in applied Bioinformatics provide reliable tools to accurately predict the peroxisomal location of proteins not yet determined experimentally. (c) 2006 Elsevier B.V. All rights reserved.