Mac-2-binding glycoproteins. Putative ligands for a cytosolic beta-galactoside lectin

J Biol Chem. 1991 Oct 5;266(28):18731-6.


Mac-2, a galactose-binding lectin secretion by activated macrophages, is the major non-integrin laminin-binding protein in these cells. Mac-2 is also expressed by epithelial cells in the intestine and kidney. We wished to identify intestinal glycoproteins other than laminin that have a high affinity for Mac-2 and that could be considered as candidate ligands or partners for this lectin in intestinal epithelium. Certain lines of human colon adenocarcinoma cells produce two Mac-2-binding glycoproteins (M2BP-1 and M2BP-2) that were identified by their avid association with Mac-2 following detergent lysis and immunoprecipitation. These glycoproteins do not share a common epitope with Mac-2, and the interaction between Mac-2 and these proteins is mediated through the carbohydrate-binding domain of Mac-2 and sugar moieties on M2BP-1 and M2BP-2. M2BP-1 (98 kDa) and M2BP-2 (70 kDa) were purified by immunoaffinity chromatography and were specifically eluted with either galactose or lactose. Peptide maps revealed that M2BP-1 and M2BP-2 are structurally related. M2BP-1 is secreted and could conceivably associate with Mac-2 extracellularly. N-terminal sequence analysis of M2BP-2 suggests that these glycoproteins represent a unique subset of candidate ligands for this mammalian beta-galactoside lectin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenocarcinoma
  • Amino Acid Sequence
  • Antigens, Differentiation / metabolism*
  • Blotting, Western
  • Colon / metabolism*
  • Epithelial Cells
  • Epithelium / metabolism
  • Galactosides / metabolism*
  • Galectin 3
  • Glycoproteins / metabolism*
  • Humans
  • Lectins / metabolism*
  • Ligands
  • Macrophages / metabolism
  • Molecular Sequence Data
  • Precipitin Tests
  • Tumor Cells, Cultured


  • Antigens, Differentiation
  • Galactosides
  • Galectin 3
  • Glycoproteins
  • Lectins
  • Ligands
  • beta-galactoside