Pex14p is not required for N-starvation induced microautophagy and in catalytic amounts for macropexophagy in Hansenula polymorpha.
We showed before that the two oppositely directed processes of peroxisome biogenesis and selective peroxisome degradation (macropexophagy) converge at the peroxisomal membrane protein Pex14p. Here we show that this protein is not required for peroxisome degradation during nitrogen starvation-induced general autophagy, thereby limiting its function to the selective degradation process. Pex14p is present in two forms, namely an unmodified (Pex14p) and a phosphorylated form (Pex14p(Pi)) that are differently induced during peroxisome proliferation. The data suggest that Pex14p is required for peroxisome biogenesis during organelle proliferation and Pex14p(Pi) in macropexophagy. Finally, we show that macropexophagy is not coupled to normal peroxisome assembly, because Pex14p is required in only catalytic amounts to allow initiation of the selective peroxisome degradation process.
de Vries
Bart
B
Laboratory of Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands.
Todde
Virginia
V
Stevens
Patricia
P
Salomons
Florian
F
van der Klei
Ida J
IJ
Veenhuis
Marten
M
D001343:Autophagy / Q000502:physiology*; D002384:Catalysis; D002478:Cells, Cultured; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D026901:Membrane Transport Proteins; D030781:Organisms, Genetically Modified; D000074401:Peroxins; D020675:Peroxisomes / Q000378:metabolism*; D010766:Phosphorylation; D010843:Pichia / Q000502:physiology*; D011489:Protein Denaturation / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013217:Starvation / Q000378:metabolism
D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C499195:PEX14 protein, S cerevisiae; D000074401:Peroxins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins