Identification of a novel effector domain of BIN1 for cancer suppression

J Cell Biochem. 2011 Oct;112(10):2992-3001. doi: 10.1002/jcb.23222.

Abstract

Bridging integrator 1 (BIN1) is a nucleocytoplasmic adaptor protein with tumor suppressor properties. The protein interacts with and inhibits the c-MYC transcription factor through the BIN1 MYC-binding domain (MBD). However, in vitro colony formation assays have clearly demonstrated that the MBD is not essential for BIN1-mediated growth arrest. We hypothesized that BIN1 contains a MYC-independent effector domain (MID) for cancer suppression. Because a functionally unique domain frequently contains a distinct structure, the human full-length BIN1 protein was subjected to limited trypsin digestion and the digested peptides were analyzed with Edman sequencing and mass spectrometry. We identified a trypsin-resistant peptide that corresponds to amino acids 146-268 of BIN1. It encompassed part of the BAR region, a putative effector region of BIN1. Computational analysis predicted that the peptide is very likely to exhibit coiled-coil motifs, implying a potential role for this region in sustaining the BIN1 structure and function. Like MBD-deleted BIN1, the trypsin-resistant peptide of BIN1 was predominantly present in the cytoplasm and was sufficient to inhibit cancer growth, regardless of dysregulated c-MYC activity. Our results suggest that the coiled-coil BIN1 BAR peptide encodes a novel BIN1 MID domain, through which BIN1 acts as a MYC-independent cancer suppressor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Line
  • Humans
  • Mass Spectrometry
  • Neoplasms / metabolism*
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Structure, Tertiary
  • Trypsin / metabolism
  • Tumor Suppressor Proteins / chemistry*
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • BIN1 protein, human
  • Nuclear Proteins
  • Protein Isoforms
  • Tumor Suppressor Proteins
  • Trypsin