Atg21p is essential for macropexophagy and microautophagy in the yeast Hansenula polymorpha

FEBS Lett. 2004 Nov 19;577(3):491-5. doi: 10.1016/j.febslet.2004.10.055.

Abstract

ATG genes are required for autophagy-related processes that transport proteins/organelles destined for proteolytic degradation to the vacuole. Here, we describe the identification and characterisation of the Hansenula polymorpha ATG21 gene. Its gene product Hp-Atg21p, fused to eGFP, had a dual location in the cytosol and in peri-vacuolar dots. We demonstrate that Hp-Atg21p is essential for two separate modes of peroxisome degradation, namely glucose-induced macropexophagy and nitrogen limitation-induced microautophagy. In atg21 cells subjected to macropexophagy conditions, sequestration of peroxisomes tagged for degradation is initiated but fails to complete.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy*
  • Autophagy-Related Proteins
  • Cytosol / metabolism
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Genes, Fungal
  • Glucose / metabolism
  • Green Fluorescent Proteins / metabolism
  • Microscopy, Fluorescence
  • Mutation
  • Peroxisomes / metabolism
  • Peroxisomes / ultrastructure
  • Pichia / genetics
  • Pichia / growth & development
  • Pichia / metabolism*
  • Pichia / ultrastructure
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Vacuoles / metabolism

Substances

  • Atg23 protein, S cerevisiae
  • Autophagy-Related Proteins
  • Fungal Proteins
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Green Fluorescent Proteins
  • Glucose