Induction of raft-like domains by a myristoylated NAP-22 peptide and its Tyr mutant

FEBS J. 2005 Apr;272(7):1792-803. doi: 10.1111/j.1742-4658.2005.04612.x.

Abstract

The N-terminally myristoylated, 19-amino acid peptide, corresponding to the amino terminus of the neuronal protein NAP-22 (NAP-22 peptide) is a naturally occurring peptide that had been shown by fluorescence to cause the sequestering of a Bodipy-labeled PtdIns(4,5)P2 in a cholesterol-dependent manner. The present work, using differential scanning calorimetry (DSC), extends the observation that formation of a PtdIns(4,5)P2-rich domain is cholesterol dependent and shows that it also leads to the formation of a cholesterol-depleted domain. The PtdIns(4,5)P2 used in the present work is extracted from natural sources and does not contain any label and has the native acyl chain composition. Peptide-induced formation of a cholesterol-depleted domain is abolished when the sole aromatic amino acid, Tyr11 is replaced with a Leu. Despite this, the modified peptide can still sequester PtdIns(4,5)P2 into domains, probably because of the presence of a cluster of cationic residues in the peptide. Cholesterol and PtdIns(4,5)P2 also modulate the insertion of the peptide into the bilayer as revealed by 1H NOESY MAS/NMR. The intensity of cross peaks between the aromatic protons of the Tyr residue and the protons of the lipid indicate that in the presence of cholesterol there is a change in the nature of the interaction of the peptide with the membrane. These results have important implications for the mechanism by which NAP-22 affects actin reorganization in neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calmodulin-Binding Proteins / genetics*
  • Calmodulin-Binding Proteins / metabolism*
  • Calorimetry, Differential Scanning
  • Cytoskeletal Proteins / genetics*
  • Cytoskeletal Proteins / metabolism*
  • Intracellular Signaling Peptides and Proteins
  • Magnetic Resonance Spectroscopy
  • Membrane Microdomains / enzymology
  • Membrane Microdomains / metabolism*
  • Mutation
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism*
  • Temperature
  • Tyrosine / genetics
  • Tyrosine / metabolism*

Substances

  • Calmodulin-Binding Proteins
  • Cytoskeletal Proteins
  • Intracellular Signaling Peptides and Proteins
  • Nerve Tissue Proteins
  • Basp1 protein, rat
  • Tyrosine