The role of fibrin fibrils in the dissociation of a cell surface protease-inhibitor complex and evidence for the recapture of the inhibitor protein.
Colonic epithelial cells possess a cell surface protease referred to as guanidinobenzoatase (GB). Active GB can be located by the fluorescent active site directed competitive inhibitor 9-amino acridine (9AA) followed by fluorescence microscopy. The cell surface GB can be transferred to fibrin fibrils, which have a higher affinity for GB than the cell surface. The cytoplasm of colonic epithelial cells contains a protein which inhibits membrane bound GB, forming a latent form of GB or GB-inhibitor complex. This complex can also be dislodged from the epithelial cell surface due to the high affinity of fibrin for GB, with the consequent dissociation of the enzyme-inhibitor complex and solubilisation of the inhibitor. This use of fibrin has led to the demonstration of the transfer of a selective inhibitor protein from one cell surface (the donor) to a second cell surface (the target).
Steven
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FS
Department of Biochemistry and Molecular Biology, School of Biological Sciences, University of Manchester, U.K.
Blakey
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DC
D000585:Aminacrine / Q000032:analysis / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D002265:Carboxylic Ester Hydrolases / Q000032:analysis / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D003106:Colon / Q000166:cytology / Q000201:enzymology*; D010450:Endopeptidases / Q000032:analysis / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D005337:Fibrin / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D011480:Protease Inhibitors / Q000032:analysis / Q000378:metabolism*; D011485:Protein Binding
D011480:Protease Inhibitors; D000585:Aminacrine; D005337:Fibrin; D002265:Carboxylic Ester Hydrolases; C037288:guanidinobenzoate esterase; D010450:Endopeptidases