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.
Kiel
J A
JA
Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, NL-9751 NN Haren, The Netherlands. Kieljakw@biol.rug.nl
Rechinger
K B
KB
van der Klei
I J
IJ
Salomons
F A
FA
Titorenko
V I
VI
Veenhuis
M
M
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