Extracellular and transmembrane region of a podocalyxin-like protein 1 fragment identified from colon cancer cell lines

Cell Biol Int. 2007 Dec;31(12):1518-24. doi: 10.1016/j.cellbi.2007.06.017. Epub 2007 Jul 15.


Regulated intramembrane proteolysis of membrane proteins has been shown to play an important role in cell differentiation and in the pathogenesis of diseases. The aim of the present study was to identify novel peptides generated by intramembrane proteolysis. The peptides were identified in serum-free cultured (SFC) media from various cell lines by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). A 2315-Da peptide found only in medium from SFC colon cancer cell lines was identified and shown to consist of a portion of both the extracellular and transmembrane regions of human podocalyxin-like 1. This protein fragment was not found in lung or pancreatic cancer cell lines by immunoprecipitation-SELDI tests using an antibody specific to this fragment, suggesting that this human podocalyxin-like protein 1 fragment may be unique to colon cancer cell lines.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biomarkers, Tumor / isolation & purification*
  • Cell Line, Tumor
  • Colonic Neoplasms / chemistry*
  • Colonic Neoplasms / metabolism
  • Culture Media, Serum-Free / analysis
  • Humans
  • Membrane Proteins / isolation & purification*
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Neoplasm Proteins / isolation & purification*
  • Peptide Mapping*
  • Protein Structure, Tertiary
  • Sialoglycoproteins / isolation & purification*
  • Sialoglycoproteins / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods


  • Biomarkers, Tumor
  • Culture Media, Serum-Free
  • Membrane Proteins
  • Neoplasm Proteins
  • Sialoglycoproteins
  • podocalyxin