Roles of C-terminal processing, and involvement in transacylation reaction of human group IVC phospholipase A2 (cPLA2gamma)

J Biochem. 2005 May;137(5):557-67. doi: 10.1093/jb/mvi067.

Abstract

The phospholipase A2s (PLA2s) are a diverse group of enzymes that hydrolyze the sn-2 fatty acid from phospholipids and play a role in a wide range of physiological functions. A 61-kDa calcium-independent PLA2, termed cPLA2gamma, was identified as an ortholog of cPLA2alpha with approximately 30% overall sequence identity. cPLA2gamma contains a potential prenylation motif at its C terminus, and is known to have PLA2 and lysophospholipase activities, but its physiological roles have not been clarified. In the present study, we expressed various forms of recombinant cPLA2gamma, including non-prenylated and non-cleaved forms, in order to investigate the effects of C-terminal processing. We examined the expression of the wild type and non-prenylated (SCLA) forms of cPLA2gamma, and found that the SCLA form was expressed normally and retained almost full activity. Expression of the prenylated and non-cleaved form of cPLA2gamma using yeast mutants lacking prenyl protein proteases AFC1 (a-factor-converting enzyme) and RCE1 (Ras-converting enzyme) revealed decreased expression in the mutant strain compared to that in the wild type yeast, suggesting that complete C-terminal processing is important for the functional expression of cPLA2gamma. In addition, cPLA2gamma was found to have coenzyme A (CoA)-independent transacylation and lysophospholipid (LPL) dismutase (LPLase/transacylase) activities, suggesting that it may be involved in fatty acid remodeling of phospholipids and the clearance of toxic lysophospholipids in cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Animals
  • Cell Line
  • Endopeptidases / genetics
  • Endopeptidases / metabolism
  • Group IV Phospholipases A2
  • Humans
  • Lysophospholipids / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Metalloendopeptidases / genetics
  • Metalloendopeptidases / metabolism
  • Models, Chemical
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Phospholipids / metabolism
  • Proprotein Convertases
  • Protein Processing, Post-Translational / physiology
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Spodoptera

Substances

  • Lysophospholipids
  • Membrane Proteins
  • Phospholipids
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • Phospholipases A
  • Group IV Phospholipases A2
  • Phospholipases A2
  • Endopeptidases
  • Proprotein Convertases
  • RCE1 protein, S cerevisiae
  • Metalloendopeptidases
  • STE24 protein, S cerevisiae