PMID- 10233149
OWN - NLM
STAT- MEDLINE
DCOM- 19990630
LR  - 20190412
IS  - 1059-1524 (Print)
IS  - 1059-1524 (Linking)
VI  - 10
IP  - 5
DP  - 1999 May
TI  - Glucose-induced autophagy of peroxisomes in Pichia pastoris requires a unique
      E1-like protein.
PG  - 1353-66
AB  - Cytosolic and peroxisomal enzymes necessary for methanol assimilation are
      synthesized when Pichia pastoris is grown in methanol. Upon adaptation from
      methanol to a glucose environment, these enzymes are rapidly and selectively
      sequestered and degraded within the yeast vacuole. Sequestration begins when the 
      vacuole changes shape and surrounds the peroxisomes. The opposing membranes then 
      fuse, engulfing the peroxisome. In this study, we have characterized a mutant
      cell line (glucose-induced selective autophagy), gsa7, which is defective in
      glucose-induced selective autophagy of peroxisomes, and have identified the GSA7 
      gene. Upon glucose adaptation, gsa7 cells were unable to degrade peroxisomal
      alcohol oxidase. We observed that the peroxisomes were surrounded by the vacuole,
      but complete uptake into the vacuole did not occur. Therefore, we propose that
      GSA7 is not required for initiation of autophagy but is required for bringing the
      opposing vacuolar membranes together for homotypic fusion, thereby completing
      peroxisome sequestration. By sequencing the genomic DNA fragment that
      complemented the gsa7 phenotype, we have found that GSA7 encodes a protein of 71 
      kDa (Gsa7p) with limited sequence homology to a family of ubiquitin-activating
      enzymes, E1. The knockout mutant gsa7Delta had an identical phenotype to gsa7,
      and both mutants were rescued by an epitope-tagged Gsa7p (Gsa7-hemagglutinin
      [HA]). In addition, a GSA7 homolog, APG7, a protein required for autophagy in
      Saccharomyces cerevisiae, was capable of rescuing gsa7. We have sequenced the
      human homolog of GSA7 and have shown many regions of identity between the yeast
      and human proteins. Two of these regions align to the putative ATP-binding domain
      and catalytic site of the family of ubiquitin activating enzymes, E1 (UBA1, UBA2,
      and UBA3). When either of these sites was mutated, the resulting mutants
      [Gsa7(DeltaATP)-HA and Gsa7(C518S)-HA] were unable to rescue gsa7 cells. We
      provide evidence to suggest that Gsa7-HA formed a thio-ester linkage with a 25-30
      kDa protein. This conjugate was not observed in cells expressing
      Gsa7(DeltaATP)-HA or in cells expressing Gsa7(C518S)-HA. Our results suggest that
      this unique E1-like enzyme is required for homotypic membrane fusion, a late
      event in the sequestration of peroxisomes by the vacuole.
FAU - Yuan, W
AU  - Yuan W
AD  - Department of Anatomy and Cell Biology, University of Florida College of
      Medicine, Gainesville, Florida 32610, USA.
FAU - Stromhaug, P E
AU  - Stromhaug PE
FAU - Dunn, W A Jr
AU  - Dunn WA Jr
LA  - eng
SI  - GENBANK/AF094516
SI  - GENBANK/AF098976
GR  - AM-33326/AM/NIADDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Mol Biol Cell
JT  - Molecular biology of the cell
JID - 9201390
RN  - 0 (ATG7 protein, S cerevisiae)
RN  - 0 (Fungal Proteins)
RN  - 0 (GSA7 protein, Pichia pastoris)
RN  - 0 (Saccharomyces cerevisiae Proteins)
RN  - 0 (UBA2 protein, human)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - EC 2.3.2.27 (Ubiquitin-Protein Ligases)
RN  - EC 6.- (Ligases)
RN  - EC 6.2.1.45 (Autophagy-Related Protein 7)
RN  - EC 6.2.1.45 (Ubiquitin-Activating Enzymes)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Adaptation, Physiological
MH  - Adenosine Triphosphate/metabolism
MH  - Amino Acid Sequence
MH  - Autophagy/*physiology
MH  - Autophagy-Related Protein 7
MH  - Base Sequence
MH  - Binding Sites
MH  - Catalytic Domain
MH  - Fungal Proteins/*genetics/*metabolism
MH  - Glucose/metabolism
MH  - Humans
MH  - Ligases/genetics
MH  - Microbodies/*metabolism
MH  - Molecular Sequence Data
MH  - Mutation
MH  - Pichia/genetics/*metabolism
MH  - *Saccharomyces cerevisiae Proteins
MH  - Sequence Homology, Amino Acid
MH  - Ubiquitin-Activating Enzymes
MH  - Ubiquitin-Protein Ligases
PMC - PMC25277
EDAT- 1999/05/08 02:13
MHDA- 2001/03/28 10:01
CRDT- 1999/05/08 02:13
PHST- 1999/05/08 02:13 [pubmed]
PHST- 2001/03/28 10:01 [medline]
PHST- 1999/05/08 02:13 [entrez]
AID - 10.1091/mbc.10.5.1353 [doi]
PST - ppublish
SO  - Mol Biol Cell. 1999 May;10(5):1353-66. doi: 10.1091/mbc.10.5.1353.