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Atg8 is essential for macropexophagy in Hansenula polymorpha.

Iryna Monastyrska·Meis van der Heide·Arjen M Krikken·Jan A K W Kiel·Ida J van der Klei·Marten Veenhuis
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Abstract

We have isolated a peroxisome-degradation-deficient (pdd) mutant of the methylotrophic yeast Hansenula polymorpha via gene tagging mutagenesis. Sequencing revealed that the mutant was affected in the HpATG8 gene. HpAtg8 is a protein with high sequence similarity to both Pichia pastoris and Saccharomyces cerevisiae Atg8 and appeared to be essential for selective peroxisome degradation (macropexophagy) and nitrogen-limitation induced microautophagy. Fluorescence microscopy revealed that a GFP.Atg8 fusion protein was located close to the vacuole. After induction of macropexophagy, the GFP.Atg8 containing spot extended to engulf an individual peroxisome. In cells of a constructed deletion strain, sequestration of individual organelles was never completed; analysis of series of serial sections revealed that invariably a minor diaphragm-like opening remained. We hypothesize that H. polymorpha Atg8 facilitates sealing of the sequestering membranes during selective peroxisome degradation.

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Amino Acid SequenceAutophagyBiological TransportFungal ProteinsGene DeletionGreen Fluorescent ProteinsImmunohistochemistryMicroscopy, ConfocalMolecular Sequence DataPeroxisomesPichiaRecombinant Fusion ProteinsSequence Homology, Amino AcidJournal ArticleResearch Support, Non-U.S. Gov't

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Iryna Monastyrska, Meis van der Heide, Arjen M Krikken, Jan A K W Kiel, Ida J van der Klei, Marten Veenhuis. 2005. Atg8 is essential for macropexophagy in Hansenula polymorpha.. https://doi.org/10.1111/j.1600-0854.2004.00252.x

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