Proteomic analysis of the cell-surface membrane in chronic lymphocytic leukemia: identification of two novel proteins, BCNP1 and MIG2B

Leukemia. 2003 Aug;17(8):1605-12. doi: 10.1038/sj.leu.2402993.


B-cell-specific plasma-membrane proteins are potential targets for either small molecule or antibody-based therapies. We have sought to annotate proteins expressed at the cell surface membrane in patients with chronic lymphocytic leukemia (CLL) using plasma-membrane-based proteomic analysis to identify previously uncharacterized and potentially B-cell-specific proteins. Proteins from plasma-membrane fractions were separated on one-dimensional gels and trypsinized fractions subjected to high-throughput MALDI-TOF mass spectrometry. Using this method, many known B-cell surface antigens were detected, but also known proteins not previously described in this disease or in this cellular compartment, including cell surface receptors, membrane-associated enzymes and secreted proteins, and completely unknown proteins. To validate the method, we show that BLK, a B-cell-specific kinase, is located in the CLL-plasma-membrane fraction. We also describe two novel proteins (MIG2B and B-cell novel protein #1, BCNP1), which are expressed preferentially in B cells. MIG2B is in a highly conserved and defined gene family containing two plasma-membrane-binding ezrin/radixin/moesin domains and a pleckstrin homology domain; the Caenorhabditis elegans homolog (UNC-112) is a membrane-associated protein that colocalizes with integrin at cell-matrix adhesion complexes. BCNP1 is a completely unknown protein with three predicted transmembrane domains, with three alternatively spliced final exons. Proteomic analysis may thus define new potential therapeutic targets.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis Regulatory Proteins
  • B-Lymphocytes / chemistry*
  • B-Lymphocytes / pathology
  • Base Sequence
  • Blotting, Western
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / isolation & purification*
  • Molecular Sequence Data
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / isolation & purification*
  • Open Reading Frames
  • Protein Isoforms
  • Protein Structure, Tertiary
  • Proteomics*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Apoptosis Regulatory Proteins
  • FERMT3 protein, human
  • Membrane Proteins
  • NIBAN3 protein, human
  • Neoplasm Proteins
  • Protein Isoforms

Associated data

  • GENBANK/AY254197
  • GENBANK/AY254198
  • GENBANK/AY254199