title: Lectin-induced actin polymerization in human lymphocytes: a possible signal for mitogenesis.
abstract: Employing the DNase I inhibition assay, a decrease in G-actin is demonstrated in human mononuclear cells following stimulation with mitogenic lectins concanavalin A (Con A) and phytohemagglutinin (PHA), as well as a nonmitogenic lectin, wheat germ agglutinin (WGA). The decrease in G-actin can be prevented by pretreatment of cells with cytochalasin E, indicating that the decrease is likely due to conversion to F-actin. Thus, the receptor-mediated actin polymerization is common to both the mitogenic as well as the nonmitogenic lectins. The maximal decrease in G-actin with Con A and PHA occurs at the same concentrations of the lectins that give optimal mitogenic responses. It is a distinct possibility that actin polymerization could be one of the signals necessary for the initiation of mitogenesis. The difference between a mitogenic and a nonmitogenic lectin may lie in the fact that a second signal (or signals), derived from macrophages, may not be generated by a nonmitogenic lectin such as WGA.
mesh_terms: D000199:Actins / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D007700:Kinetics; D037102:Lectins; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology / Q000502:physiology*; D046911:Macromolecular Substances
chemical_list: D000199:Actins; D037102:Lectins; D046911:Macromolecular Substances