The Hansenula polymorpha PDD1 gene product, essential for the selective degradation of peroxisomes, is a homologue of Saccharomyces cerevisiae Vps34p.
Via functional complementation we have isolated the Hansenula polymorpha PDD1 gene essential for selective, macroautophagic peroxisome degradation. HpPDD1 encodes a 116 kDa protein with high similarity (42% identity) to Saccharomyces cerevisiae Vps34p, which has been implicated in vacuolar protein sorting and endocytosis. Western blotting experiments revealed that HpPDD1 is expressed constitutively. In a H. polymorpha pdd1 disruption strain peroxisome degradation is fully impaired. Sequestered peroxisomes, typical for the first stage of peroxisome degradation in H. polymorpha, were never observed, suggesting that HpPdd1p plays a role in the tagging of redundant peroxisomes and/or sequestration of these organelles from the cytosol. Possibly, HpPdd1p is the functional homologue of ScVps34p, because-like S. cerevisiae vps34 mutants-H. polymorpha pdd1 mutants are temperature-sensitive for growth and are impaired in the sorting of vacuolar carboxypeptidase Y. Moreover, HpPdd1p is associated to membranes, as was also observed for ScVps34p.
Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, NL-9751 NN Haren, The Netherlands. Kieljakw@biol.rug.nl
J A
JA
Kiel
K B
KB
Rechinger
I J
IJ
van der Klei
F A
FA
Salomons
V I
VI
Titorenko
M
M
Veenhuis
D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000595:Amino Acid Sequence; D001692:Biological Transport; D002268:Carboxypeptidases / Q000235:genetics / Q000378:metabolism; D043402:Cathepsin A; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008830:Microbodies / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry / Q000235:genetics*; D010843:Pichia / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014617:Vacuoles / Q000201:enzymology / Q000648:ultrastructure
D000429:Alcohol Oxidoreductases; D002268:Carboxypeptidases; D043402:Cathepsin A; D005656:Fungal Proteins; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; C120506:Pdd1 protein, Hansenula; C019643:alcohol oxidase