Localization and targeting of isocitrate lyases in Saccharomyces cerevisiae

Biochem J. 1996 Oct 1;319 ( Pt 1)(Pt 1):255-62. doi: 10.1042/bj3190255.

Abstract

Native isocitrate lyase from castor bean and a C-terminally truncated variant were expressed in Saccharomyces cerevisiae under the control of a galactose-inducible promoter. Both forms of isocitrate lyase were targeted to the yeast peroxisomes. They co-fractionated with catalase on sucrose-density-gradient centrifugation of a post-nuclear supernatant prepared from cells grown on oleic acid plus galactose, but were found in the cytosolic fractions when the cells were grown under conditions that repress peroxisome formation. The endogenous S. cerevisiae isocitrate lyase was found solely in the cytoplasmic fractions, even under growth conditions that induce peroxisome proliferation. This result shows that the presence of isocitrate lyase in peroxisomes is not essential for a functional glyoxylate cycle. Although the heterologous enzyme was transported to peroxisomes it was not enzymically active. Immunocytochemical studies provide independent evidence that the plant enzyme is imported into the matrix of yeast peroxisomes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Biological Transport
  • Conserved Sequence
  • Cytosol / enzymology
  • Electrophoresis, Polyacrylamide Gel
  • Enterobacteriaceae / enzymology
  • Fungi / enzymology
  • Isocitrate Lyase / isolation & purification
  • Isocitrate Lyase / metabolism*
  • Microbodies / enzymology
  • Mitochondria / enzymology
  • Molecular Sequence Data
  • Plants / enzymology
  • Plasmids / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / ultrastructure
  • Sequence Alignment

Substances

  • Isocitrate Lyase