Glycolipozyme membrane protein integrase (MPIase): recent data

Biomol Concepts. 2014 Oct;5(5):429-38. doi: 10.1515/bmc-2014-0030.


A novel factor for membrane protein integration, from the cytoplasmic membrane of Escherichia coli, named MPIase (membrane protein integrase), has recently been identified and characterized. MPIase was revealed to be essential for the membrane integration of a subset of membrane proteins, despite that such integration reactions have been, thus far, thought to occur spontaneously. The structure determination study revealed that MPIase is a novel glycolipid comprising a glycan chain with three N-acetylated amino sugars connected to diacylglycerol through a pyrophosphate linker. As MPIase catalyzes membrane protein integration, we propose that MPIase is a glycolipozyme on the basis of its enzyme-like function. The glycan chain exhibits a molecular chaperone-like function by directly interacting with substrate membrane proteins. Moreover, MPIase also affects the dimer structure of SecYEG, a translocon, thereby significantly stimulating preprotein translocation. The molecular mechanisms of MPIase functions will be outlined.

Publication types

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

MeSH terms

  • Escherichia coli / chemistry
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / metabolism*
  • Glycolipids / chemistry
  • Glycolipids / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism
  • Membrane Transport Proteins / chemistry*
  • Membrane Transport Proteins / metabolism*
  • SEC Translocation Channels


  • Escherichia coli Proteins
  • Glycolipids
  • Membrane Proteins
  • Membrane Transport Proteins
  • SEC Translocation Channels
  • YIDC protein, E coli