title: Characterization of a beta-actinin-like protein in purified non-muscle cell membranes. Its activity on (Na+ + K+)-ATPase.
abstract: Treatment by EDTA of purified plasma membranes from MF2S cells (a variant of the murine plasmacytoma MOPC 173) solubilized proteins and increased by a 1000-fold the sensitivity of (Na+ + K+)-ATPase to ouabain. When added back with Ca2+ to treated plasma membranes, these EDTA-solubilized proteins restored the initial sensitivity of the enzyme to its inhibitor. We report the purification of a protein of Mr 32000, isolated from the EDTA-treated membrane supernatant. This protein was purified by a one-step procedure involving a preparative polyacrylamide gel electrophoresis without detergent. In the presence of Ca2+ it was able to restore the original sensitivity to ouabain of (Na+ + K+)-ATPase from EDTA-treated membrane. This protein was shown to be similar to the beta-actinin described by Maruyama by the following criteria: (1) molecular weight and amino acid composition; (2) cross-reactivity with their respective antisera; (3) in the presence of Ca2+ the same quantitative biological activity on ouabain sensitivity of the (Na+ + K+)-ATPase. A possible interaction between beta-actinin, calmodulin and membrane-bound (Na+ + K+)-ATPase is discussed.
mesh_terms: D000185:Actinin; D000199:Actins / Q000302:isolation & purification; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002645:Chickens; D008565:Membrane Proteins / Q000302:isolation & purification* / Q000502:physiology; D051379:Mice; D009132:Muscles / Q000378:metabolism; D010954:Plasmacytoma / Q000378:metabolism; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014335:Tropomyosin / Q000302:isolation & purification
chemical_list: D000199:Actins; D000596:Amino Acids; D008565:Membrane Proteins; D014335:Tropomyosin; D000185:Actinin; D000254:Sodium-Potassium-Exchanging ATPase