The assembly of proline-rich membrane anchor (PRiMA)-linked acetylcholinesterase enzyme: glycosylation is required for enzymatic activity but not for oligomerization

J Biol Chem. 2011 Sep 23;286(38):32948-61. doi: 10.1074/jbc.M111.261248. Epub 2011 Jul 27.

Abstract

Acetylcholinesterase (AChE) anchors onto cell membranes by a transmembrane protein PRiMA (proline-rich membrane anchor) as a tetrameric form in vertebrate brain. The assembly of AChE tetramer with PRiMA requires the C-terminal "t-peptide" in AChE catalytic subunit (AChE(T)). Although mature AChE is well known N-glycosylated, the role of glycosylation in forming the physiologically active PRiMA-linked AChE tetramer has not been studied. Here, several lines of evidence indicate that the N-linked glycosylation of AChE(T) plays a major role for acquisition of AChE full enzymatic activity but does not affect its oligomerization. The expression of the AChE(T) mutant, in which all N-glycosylation sites were deleted, together with PRiMA in HEK293T cells produced a glycan-depleted PRiMA-linked AChE tetramer but with a much higher K(m) value as compared with the wild type. This glycan-depleted enzyme was assembled in endoplasmic reticulum but was not transported to Golgi apparatus or plasma membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholinesterase / chemistry*
  • Acetylcholinesterase / metabolism*
  • Animals
  • Biocatalysis
  • Chickens
  • Enzyme Stability
  • GPI-Linked Proteins / chemistry
  • GPI-Linked Proteins / metabolism
  • Glycosylation
  • HEK293 Cells
  • Humans
  • Membrane Proteins / metabolism*
  • Mice
  • Nerve Tissue Proteins / metabolism*
  • Polysaccharides / metabolism
  • Protein Binding
  • Protein Multimerization
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Transport
  • Recombinant Proteins / metabolism

Substances

  • GPI-Linked Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Polysaccharides
  • Recombinant Proteins
  • prima1 protein, mouse
  • ACHE protein, human
  • Acetylcholinesterase