The role of extracted cell surface molecules in mouse teratocarcinoma cell adhesion

Proteins and glycoproteins associated with cell surfaces are thought to be important in mediating selective cellular adhesion (9,21,26,29), while the lipid elements may also be involved (4). In isolating cell surface adhesion proteins for study, biological activity may be lost due to the harsh chemical environments of the extraction procedures. This loss of activity may be due to a distortion of the protein's tertiary and quaternary structures (organization). Electrophoretic extraction of such surface components of live cells (6) when carried out under mild conditions should limit potential structural damage and preserve the in vivo function. By applying this technique to mouse teratocarcinoma some progress has been made in understanding the role of extracted membrane molecules in the adhesiveness of these cells. The protein fraction of an electrophoretic extract of mouse ascites teratocarcinoma has been isolated and appears to be involved in teratocarcinoma cell adhesion. Nonadhering ascites teratocarcinoma cells show substantially increased adhesiveness in the presence of the extract while other cell types do not. In addition, the extract aggregates fixed cells and may bind to surface carbohydrates.