Structural, in silico, and functional analysis of a Disabled-2-derived peptide for recognition of sulfatides

Sci Rep. 2020 Aug 11;10(1):13520. doi: 10.1038/s41598-020-70478-0.

Abstract

Disabled-2 (Dab2) is an adaptor protein that regulates the extent of platelet aggregation by two mechanisms. In the first mechanism, Dab2 intracellularly downregulates the integrin αIIbβ3 receptor, converting it to a low affinity state for adhesion and aggregation processes. In the second mechanism, Dab2 is released extracellularly and interacts with the pro-aggregatory mediators, the integrin αIIbβ3 receptor and sulfatides, blocking their association to fibrinogen and P-selectin, respectively. Our previous research indicated that a 35-amino acid region within Dab2, which we refer to as the sulfatide-binding peptide (SBP), contains two potential sulfatide-binding motifs represented by two consecutive polybasic regions. Using molecular docking, nuclear magnetic resonance, lipid-binding assays, and surface plasmon resonance, this work identifies the critical Dab2 residues within SBP that are responsible for sulfatide binding. Molecular docking suggested that a hydrophilic region, primarily mediated by R42, is responsible for interaction with the sulfatide headgroup, whereas the C-terminal polybasic region contributes to interactions with acyl chains. Furthermore, we demonstrated that, in Dab2 SBP, R42 significantly contributes to the inhibition of platelet P-selectin surface expression. The Dab2 SBP residues that interact with sulfatides resemble those described for sphingolipid-binding in other proteins, suggesting that sulfatide-binding proteins share common binding mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Amino Acid Sequence
  • Animals
  • Apoptosis Regulatory Proteins / chemistry*
  • Computer Simulation*
  • Humans
  • Models, Molecular
  • P-Selectin / metabolism
  • Peptide Fragments / chemistry*
  • Peptide Fragments / metabolism*
  • Protein Binding
  • Protein Conformation
  • Sulfoglycosphingolipids / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • DAB2 protein, human
  • P-Selectin
  • Peptide Fragments
  • Sulfoglycosphingolipids