Enzymatic basis for the Ca2+-induced cross-linking of membrane proteins in intact human erythrocytes.
The accumulation of Ca2+ ions in intact human erythrocytes leads to the production of membrane protein polymers larger than spectrin. The polymer has a heterogeneous size distribution and is rich in gamma-glutamyl-epsilon-lysine cross-links. Isolation of this isodipeptide, in amounts as high as 6 mol/10(5) g of protein, confirms the idea [Lorand L., Weissmann, L.B., Epel, D.L., and Bruner-Lorand, J. (1976), Proc. Natl. Acad. Sci. U.S.A. 73, 4479] that the Ca2+-induced membrane protein polymerization is mediated by transglutaminase. Formation of the polymer in the intact cells is inhibited by the addition of small, water-soluble primary amines. Inasmuch as these amines are known to prevent the Ca2+-dependent loss of deformability of the membrane, it is suggested that transglutaminase-catalyzed cross-linking may be a biochemical cause of irreversible membrane stiffening.
D000596:Amino Acids / Q000032:analysis; D002118:Calcium / Q000494:pharmacology*; D004151:Dipeptides / Q000032:analysis; D004789:Enzyme Activation; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000097:blood*; D011485:Protein Binding; D013049:Spectrin; D005723:gamma-Glutamyltransferase / Q000097:blood
D000596:Amino Acids; D004151:Dipeptides; D046911:Macromolecular Substances; D008565:Membrane Proteins; D013049:Spectrin; D005723:gamma-Glutamyltransferase; D002118:Calcium