This article is part of the supplement: Seventh International Conference on Bioinformatics (InCoB2008)
Predicted mouse peroxisome-targeted proteins and their actual subcellular locations
1 Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Hidaka, Saitama 350-1241, Japan
2 Immunoinformatics Team, Advanced Genome Information Group, RIKEN Genomic Sciences Center, RIKEN Yokohama Institute, Yokohama, Kanagawa 230-0045, Japan
3 RIKEN Advanced Science Institute (ASI), MetaSystems Research Team, Yokohama, Kanagawa 230-0045, Japan
4 Cambridge Centre for Neuropsychiatric Research (CCNR), Institute of Biotechnology, University of Cambridge, Cambridge CB2 1QT, UK
5 Division of Genomics and Genetics, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
BMC Bioinformatics 2008, 9(Suppl 12):S16 doi:10.1186/1471-2105-9-S12-S16Published: 12 December 2008
The import of most intraperoxisomal proteins is mediated by peroxisome targeting signals at their C-termini (PTS1) or N-terminal regions (PTS2). Both signals have been integrated in subcellular location prediction programs. However their present performance, particularly of PTS2-targeting did not seem fitting for large-scale screening of sequences.
We modified an earlier reported PTS1 screening method to identify PTS2-containing mouse candidates using a combination of computational and manual annotation. For rapid confirmation of five new PTS2- and two previously identified PTS1-containing candidates we developed the new cell line CHO-perRed which stably expresses the peroxisomal marker dsRed-PTS1. Using CHO-perRed we confirmed the peroxisomal localization of PTS1-targeted candidate Zadh2. Preliminary characterization of Zadh2 expression suggested non-PPARα mediated activation. Notably, none of the PTS2 candidates located to peroxisomes.
In a few cases the PTS may oscillate from "silent" to "functional" depending on its surface accessibility indicating the potential for context-dependent conditional subcellular sorting. Overall, PTS2-targeting predictions are unlikely to improve without generation and integration of new experimental data from location proteomics, protein structures and quantitative Pex7 PTS2 peptide binding assays.