The type-2 peroxisomal targeting signal

Biochim Biophys Acta Mol Cell Res. 2020 Feb;1867(2):118609. doi: 10.1016/j.bbamcr.2019.118609. Epub 2019 Nov 18.


The type-2 peroxisomal targeting signal (PTS2) is one of two peptide motifs destining soluble proteins for peroxisomes. This signal acts as amphiphilic α-helix exposing the side chains of all conserved residues to the same side. PTS2 motifs are recognized by a bipartite protein complex consisting of the receptor PEX7 and a co-receptor. Cargo-loaded receptor complexes are translocated across the peroxisomal membrane by a transient pore and inside peroxisomes, cargo proteins are released and processed in many, but not all species. The components of the bipartite receptor are re-exported into the cytosol by a ubiquitin-mediated and ATP-driven export mechanism. Structurally, PTS2 motifs resemble other N-terminal targeting signals, whereas the functional relation to the second peroxisomal targeting signal (PTS1) is unclear. Although only a few PTS2-carrying proteins are known in humans, subjects lacking a functional import mechanism for these proteins suffer from the severe inherited disease rhizomelic chondrodysplasia punctata.

Keywords: Evolution; PTS2; Peptide recognition; Peroxisomes; Protein transport; Targeting signals.

Publication types

  • Review

MeSH terms

  • Amino Acid Motifs
  • Chondrodysplasia Punctata, Rhizomelic / metabolism
  • Chondrodysplasia Punctata, Rhizomelic / pathology
  • Humans
  • Membrane Proteins / metabolism
  • Peroxisomal Targeting Signal 2 Receptor / chemistry
  • Peroxisomal Targeting Signal 2 Receptor / genetics
  • Peroxisomal Targeting Signal 2 Receptor / metabolism*
  • Peroxisomes / metabolism
  • Protein Domains
  • Protein Structure, Quaternary
  • Protein Transport


  • Membrane Proteins
  • Peroxisomal Targeting Signal 2 Receptor