14-3-3 sigma isoform interacts with the cytoplasmic domain of the transmembrane BP180 in keratinocytes

J Cell Physiol. 2007 Sep;212(3):675-81. doi: 10.1002/jcp.21064.

Abstract

The protein bullous pemphigoid antigen-2 (BPAG2/BP180/collagen type XVII) plays a key role in attachment of basal keratinocytes to epidermal basement membrane. The binding of BP180 with either integrin alpha6, integrin beta4, or bullous pemphigoid antigen-1 (BPAG1/BP230) is critical for this attachment in skin. The protein 14-3-3 sigma, also known as stratifin and a marker for epithelial cells, is a member of a highly conserved small acidic 14-3-3 protein family naturally found in all eukaryotic cells. Here, we have used a 14-3-3sigma GST pull-down screening assay and showed that sigma (sigma) isoform of the 14-3-3 protein family interacts with the cytoplasmic N-terminal domain of BP180. Analysis of a series of truncated or deleted 14-3-3sigma revealed that only intact 14-3-3sigma molecule, but not any of its fragments can interact with BP180. This finding suggests that conformation and possible dimerization of 14-3-3 sigma is essential for this interaction. Further, a BP180 co-immunoprecipitation (IP) and its reverse IP assays were conducted and the results confirmed that 14-3-3 sigma interacts with cytoplasmic domain, but not ecto-domain of the BP180. In conclusion, the finding of this study provides evidence that 14-3-3sigma isoform interacts with BP180 which is a major component of hemidesmosome involved in the attachment of epidermis to the basement membrane in skin. However, the significance of this interaction in hemidesmosome formation and/or attachment needs to be explored.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins
  • Autoantigens / chemistry
  • Autoantigens / metabolism*
  • Biomarkers, Tumor / chemistry
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism*
  • Carrier Proteins
  • Cell Membrane / enzymology
  • Cell Membrane / metabolism*
  • Cells, Cultured
  • Collagen Type XVII
  • Cytoplasm / enzymology
  • Cytoplasm / metabolism*
  • Cytoskeletal Proteins
  • Dimerization
  • Dystonin
  • Exonucleases / chemistry
  • Exonucleases / genetics
  • Exonucleases / metabolism*
  • Exoribonucleases
  • Humans
  • Immunoprecipitation
  • Keratinocytes / enzymology
  • Keratinocytes / metabolism*
  • Molecular Weight
  • Mutation
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Nerve Tissue Proteins
  • Non-Fibrillar Collagens / chemistry
  • Non-Fibrillar Collagens / metabolism*
  • Peptide Fragments / metabolism
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / metabolism

Substances

  • 14-3-3 Proteins
  • Autoantigens
  • Biomarkers, Tumor
  • Carrier Proteins
  • Cytoskeletal Proteins
  • DST protein, human
  • Dystonin
  • Neoplasm Proteins
  • Nerve Tissue Proteins
  • Non-Fibrillar Collagens
  • Peptide Fragments
  • Recombinant Fusion Proteins
  • Exonucleases
  • Exoribonucleases
  • SFN protein, human