title: Atg21p is essential for macropexophagy and microautophagy in the yeast Hansenula polymorpha.
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.
authors.affiliation: Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
authors.forename: Adriana N
authors.initials: AN
authors.lastname: Leão-Helder
authors.forename: Arjen M
authors.initials: AM
authors.lastname: Krikken
authors.forename: Gerd
authors.initials: G
authors.lastname: Gellissen
authors.forename: Ida J
authors.initials: IJ
authors.lastname: van der Klei
authors.forename: Marten
authors.initials: M
authors.lastname: Veenhuis
authors.forename: Jan A K W
authors.initials: JA
authors.lastname: Kiel
mesh_terms: D001343:Autophagy; D000071183:Autophagy-Related Proteins; D003600:Cytosol / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009154:Mutation; D020675:Peroxisomes / Q000378:metabolism / Q000648:ultrastructure; D010843:Pichia / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism
chemical_list: C480170:Atg23 protein, S cerevisiae; D000071183:Autophagy-Related Proteins; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D005947:Glucose