title: Changes in the organization of actin and myosin in non-muscle cells induced by N-ethylmaleimide.
abstract: There is evidence from in vitro studies that the SH reagent N-ethylmaleimide (NEM) causes the formation of ATP-resistant rigor-complexes between actin and myosin, and NEM-modified heavy meromyosin has been used by Cande et al. to study the contractile process during cytokinesis. It is reported here that treatment of tissue-cultured cells with NEM causes an immediate cessation of all motile activities and a simultaneous stabilization of the ultrastructure of the cell visualized on lysis with detergent-containing buffers. After NEM treatment a 5- to 10-fold increase in the amount of myosin was found associated with the detergent-resistant cell residues. As suggested by immunoelectron microscopy, using antibodies to non-muscle myosin together with gold-labelled protein A, increasing amounts of myosin filaments became associated with the microfilament assemblies of the cell with time of NEM treatment. In addition to this there was a slow, progressive reorganization of the cortical wave of microfilaments. The structures interpreted as myosin filaments were visualized at relatively high resolution. The immunoelectron microscopy finally also indicated the presence of a non-filamentous form of myosin in agreement with the results of others.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003101:Collodion; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D003902:Detergents; D004591:Electrophoresis, Polyacrylamide Gel; D005033:Ethylmaleimide / Q000494:pharmacology*; D005347:Fibroblasts / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005910:Glioma / Q000378:metabolism; D006046:Gold; D006801:Humans; D007120:Immunochemistry; D008854:Microscopy, Electron / Q000379:methods; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism; D013205:Staphylococcal Protein A
chemical_list: D000199:Actins; D003902:Detergents; D013205:Staphylococcal Protein A; D006046:Gold; D000255:Adenosine Triphosphate; D003101:Collodion; D009218:Myosins; D005033:Ethylmaleimide