Saccharomyces cerevisiae acyl-CoA oxidase follows a novel, non-PTS1, import pathway into peroxisomes that is dependent on Pex5p.
The peroxisomal protein acyl-CoA oxidase (Pox1p) of Saccharomyces cerevisiae lacks either of the two well characterized peroxisomal targeting sequences known as PTS1 and PTS2. Here we demonstrate that peroxisomal import of Pox1p is nevertheless dependent on binding to Pex5p, the PTS1 import receptor. The interaction between Pex5p and Pox1p, however, involves novel contact sites in both proteins. The interaction region in Pex5p is located in a defined area of the amino-terminal part of the protein outside of the tetratricopeptide repeat domain involved in PTS1 recognition; the interaction site in Pox1p is located internally and not at the carboxyl terminus where a PTS1 is normally found. By making use of pex5 mutants that are either specifically disturbed in binding of PTS1 proteins or in binding of Pox1p, we demonstrate the existence of two independent, Pex5p-mediated import pathways into peroxisomes in yeast as follows: a classical PTS1 pathway and a novel, non-PTS1 pathway for Pox1p.
Klein
Andre T J
AT
Department of Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, The Netherlands.
van den Berg
Marlene
M
Bottger
Gina
G
Tabak
Henk F
HF
Distel
Ben
B
D042962:Acyl-CoA Oxidase; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000378:metabolism*; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; D010088:Oxidoreductases; D042962:Acyl-CoA Oxidase; C467991:POX1 protein, S cerevisiae