Abstract
Within the extended receptor cycle of peroxisomal matrix import, the function of the import receptor Pex5p comprises cargo recognition and transport. While the C-terminal half (Pex5p-C) is responsible for PTS1 binding, the contribution of the N-terminal half of Pex5p (Pex5p-N) to the receptor cycle has been less clear. Here we demonstrate, using different techniques, that in Saccharomyces cerevisiae Pex5p-N alone facilitates the import of the major matrix protein Fox1p. This finding suggests that Pex5p-N is sufficient for receptor docking and cargo transport into peroxisomes. Moreover, we found that Pex5p-N can be functionally replaced by Pex18p, one of two auxiliary proteins of the PTS2 import pathway. A chimeric protein consisting of Pex18p (without its Pex7p binding site) fused to Pex5p-C is able to partially restore PTS1 protein import in a PEX5 deletion strain. On the basis of these results, we propose that the auxiliary proteins of the PTS2 import pathway fulfill roles similar to those of the N-terminal half of Pex5p in the PTS1 import pathway.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Acyl-CoA Oxidase / genetics
-
Acyl-CoA Oxidase / metabolism*
-
Biological Transport / physiology
-
Fungal Proteins / genetics
-
Fungal Proteins / metabolism*
-
Humans
-
Intracellular Membranes / metabolism
-
Membrane Transport Proteins / genetics
-
Membrane Transport Proteins / metabolism*
-
Peroxisomal Targeting Signal 2 Receptor
-
Peroxisome-Targeting Signal 1 Receptor
-
Peroxisomes / metabolism
-
Peroxisomes / ultrastructure
-
Receptors, Cytoplasmic and Nuclear / metabolism*
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / metabolism
-
Saccharomyces cerevisiae / genetics
-
Saccharomyces cerevisiae / metabolism
-
Saccharomyces cerevisiae Proteins / genetics
-
Saccharomyces cerevisiae Proteins / metabolism*
Substances
-
Fungal Proteins
-
Membrane Transport Proteins
-
PEX18 protein, S cerevisiae
-
PEX5 protein, S cerevisiae
-
Peroxisomal Targeting Signal 2 Receptor
-
Peroxisome-Targeting Signal 1 Receptor
-
Receptors, Cytoplasmic and Nuclear
-
Recombinant Fusion Proteins
-
Saccharomyces cerevisiae Proteins
-
Acyl-CoA Oxidase
-
POX1 protein, S cerevisiae