title: Effect of proteases on activation of resting chick embryo fibroblasts and on cell surface proteins.
abstract: The relationship between activation of resting chick embryo fibroblasts by proteases and proteolytic alteration of the cell surface has been investigated. Five different proteases were examined: trypsin, collagenase, plasmin, alpha-chymotrypsin, and thrombin. All of these proteases, when added to the culture medium at concentrations of 0.08-2.2 mug/ml, stimulated deoxyglucose uptake and induced cell division. The absolute levels of stimulation depended on the specific protease. Activation ranged from a doubling in cell number in 24 hr for trypsin and thrombin down to a 47% increase in cell number for alpha-chymotrypsin. Except in the case of thrombin, the stimulatory effects of these proteases correlated with breakdown of Z, a protein which is the major chick surface protein as revealed by lactoperoxidase-catalyzed iodination and which disappears upon transformation. In the case of thrombin, stimulatory concentrations brought about no detectable loss of surface components. Thus loss of Z is not a necessary condition for activation of chick fibroblasts; it may be a sufficient condition for activation of part of the cell population.
mesh_terms: D002455:Cell Division / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D002918:Chymotrypsin / Q000494:pharmacology; D003470:Culture Media; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000494:pharmacology; D005341:Fibrinolysin / Q000494:pharmacology; D007074:Immunoglobulin G / Q000378:metabolism; D003012:Microbial Collagenase / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D012260:Ribonucleases / Q000494:pharmacology; D013499:Surface Properties; D013917:Thrombin / Q000494:pharmacology; D014357:Trypsin / Q000494:pharmacology
chemical_list: D003470:Culture Media; D003837:Deoxy Sugars; D007074:Immunoglobulin G; D011506:Proteins; D003847:Deoxyglucose; D003851:Deoxyribonucleases; D012260:Ribonucleases; D010447:Peptide Hydrolases; D002918:Chymotrypsin; D014357:Trypsin; D013917:Thrombin; D005341:Fibrinolysin; D003012:Microbial Collagenase