Differential effects of concanavalin A and succinyl concanavalin A on the macromolecular events of platelet activation.
Concanavalin A is capable of activating platelets in a concentration-dependent manner as judged by [14C]serotonin secretion from prelabeled platelets. In contrast, succinyl concanavalin A does not induce platelet secretion. Concanavalin A treatment also results in a number of alterations in platelet macromolecules which are presumably associated with the process of platelet activation. These include the phosphorylation of 20 and 47 kDa platelet proteins, the increased polymerization and association of new proteins with the platelet cytoskeleton and the association of the platelet membrane glycoprotein IIb/III complex with the platelet cytoskeleton. Succinyl concanavalin A treatment results in none of these macromolecular events. This difference is observed despite the demonstration that both lectins bind to the platelet surface. Gel overlay experiments also indicate that concanavalin A and succinyl concanavalin A bind to the same receptors. These differences in the biological effects of concanavalin A and succinyl concanavalin A on platelets may be due to decreased receptor crosslinking by the succinylated derivative. The formation of multiple linked interactions between surface receptors may be an important event in the activation of platelets by concanavalin A.
D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D003208:Concanavalin A / Q000031:analogs & derivatives* / Q000494:pharmacology*; D003599:Cytoskeleton / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000097:blood; D010766:Phosphorylation; D012701:Serotonin / Q000378:metabolism
D046911:Macromolecular Substances; D008565:Membrane Proteins; D003208:Concanavalin A; D012701:Serotonin; C019558:succinylconcanavalin A