Protein translocation into peroxisomes by ring-shaped import receptors.
Folded and functional proteins destined for translocation from the cytosol into the peroxisomal matrix are recognized by two different peroxisomal import receptors, Pex5p and Pex7p. Both cargo-loaded receptors dock on the same translocon components, followed by cargo release and receptor recycling, as part of the complete translocation process. Recent structural and functional evidence on the Pex5p receptor has provided insight on the molecular requirements of specific cargo recognition, while the remaining processes still remain largely elusive. Comparison of experimental structures of Pex5p and a structural model of Pex7p reveal that both receptors are built by ring-like arrangements with cargo binding sites, central to the respective structures. Although, molecular insight into the complete peroxisomal translocon still remains to be determined, emerging data allow to deduce common molecular principles that may hold for other translocation systems as well.
Stanley
Will A
WA
ARC Plant Energy Biology Centre M316, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Fodor
Krisztian
K
Marti-Renom
Marc A
MA
Schliebs
Wolfgang
W
Wilmanns
Matthias
M
D000595:Amino Acid Sequence; D001665:Binding Sites; D006801:Humans; D008969:Molecular Sequence Data; D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry*
D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear