Pex9p is a new yeast peroxisomal import receptor for PTS1-containing proteins.
Peroxisomal proteins carrying a type 1 peroxisomal targeting signal (PTS1) are recognized by the well-conserved cycling import receptor Pex5p. The yeast YMR018W gene encodes a Pex5p paralog and newly identified peroxin that is involved in peroxisomal import of a subset of matrix proteins. The new peroxin was designated Pex9p, and it interacts with the docking protein Pex14p and a subclass of PTS1-containing peroxisomal matrix enzymes. Unlike Pex5p, Pex9p is not expressed in glucose- or ethanol-grown cells, but it is strongly induced by oleate. Under these conditions, Pex9p acts as a cytosolic and membrane-bound peroxisome import receptor for both malate synthase isoenzymes, Mls1p and Mls2p. The inducible Pex9p-dependent import pathway provides a mechanism for the oleate-inducible peroxisomal targeting of malate synthases. The existence of two distinct PTS1 receptors, in addition to two PTS2-dependent import routes, contributes to the adaptive metabolic capacity of peroxisomes in response to environmental changes and underlines the role of peroxisomes as multi-purpose organelles. The identification of different import routes into peroxisomes contributes to the molecular understanding of how regulated protein targeting can alter the function of organelles according to cellular needs.
Abteilung Systembiochemie, Institut für Biochemie und Pathobiochemie, Abteilung Systembiochemie, Ruhr-Universität Bochum, Bochum D-44780, Germany.
Daniel
D
Effelsberg
Abteilung Systembiochemie, Institut für Biochemie und Pathobiochemie, Abteilung Systembiochemie, Ruhr-Universität Bochum, Bochum D-44780, Germany.
Luis Daniel
LD
Cruz-Zaragoza
Abteilung Systembiochemie, Institut für Biochemie und Pathobiochemie, Abteilung Systembiochemie, Ruhr-Universität Bochum, Bochum D-44780, Germany.
Wolfgang
W
Schliebs
Abteilung Systembiochemie, Institut für Biochemie und Pathobiochemie, Abteilung Systembiochemie, Ruhr-Universität Bochum, Bochum D-44780, Germany ralf.erdmann@rub.de.
Ralf
0000-0001-8380-0342
R
Erdmann
D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D008292:Malate Synthase / Q000378:metabolism; D008954:Models, Biological; D019301:Oleic Acid / Q000494:pharmacology; D020675:Peroxisomes / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D021382:Protein Sorting Signals / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D040681:Structural Homology, Protein; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
D021382:Protein Sorting Signals; D029701:Saccharomyces cerevisiae Proteins; D019301:Oleic Acid; D008292:Malate Synthase
Malate synthases; Mls1p; Mls2p; PTS1; Peroxisomal targeting signal; Peroxisome; Pex5p receptor; Pex9p; Protein import