• extracellular matrix;
  • collagen;
  • receptors;
  • integrins;
  • connective tissue

Affinity chromatography of a number of cell types on collagens I and III reveals three proteins with MRof 250, 170 and 140kDa. These proteins are able to discriminate between types I and III, but not types III and IV. Collagen-type recognition is therefore characteristic for cells of connective tissue origin. Polyclonal antibodies (Ab) raised against 170 and 140kDa polypeptides and used in immunofluorescence show membrane localisation for both, with their distribution being similar to each other and to the distribution of the integrin β1 chain. Abp140 and commercial monoclonal antibodies against α2chain stain a band of the same molecular mass as from purified collagen binding proteins from liver cells, indicating that the 140kDa protein is probably the α2integrin chain. The α2chain containing integrins are therefore able to discriminate collagen types I and III and collagen type recognition by this receptor is cell-type dependent.