Truncation of the caspase-related subunit (Gpi8p) of Saccharomyces cerevisiae GPI transamidase: Dimerization revealed

Jennifer L. Meitzler, Jeffrey J. Gray, Tamara L. Hendrickson

Research output: Contribution to journalArticlepeer-review

Abstract

Eukaryotic proteins can be post-translationally modified with a glycosylphosphatidylinositol (GPI) membrane anchor. This modification reaction is catalyzed by GPI transamidase (GPI-T), a multimeric, membrane-bound enzyme. Gpi8p, an essential component of GPI-T, shares low sequence similarity with caspases and contains all or part of the enzyme's active site [U. Meyer, M. Benghezal, I. Imhof, A. Conzelmann, Biochemistry 39 (2000) 3461-3471]. Structural predictions suggest that the soluble portion of Gpi8p is divided into two domains: a caspase-like domain that contains the active site machinery and a second, smaller domain of unknown function. Based on these predictions, we evaluated a soluble truncation of Gpi8p (Gpi823-306). Dimerization was investigated due to the known proclivity of caspases to homodimerize; a Gpi823-306 homodimer was detected by native gel and confirmed by mass spectrometry and N-terminal sequencing. Mutations at the putative caspase-like dimerization interface disrupted dimer formation. When combined, these results demonstrate an organizational similarity between Gpi8p and caspases.

Original languageEnglish (US)
Pages (from-to)83-93
Number of pages11
JournalArchives of Biochemistry and Biophysics
Volume462
Issue number1
DOIs
StatePublished - Jun 1 2007

Keywords

  • Caspases
  • Dimerization
  • GPI membrane anchor
  • GPI transamidase
  • Gpi8
  • Homodimer

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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