Electron microscopic studies of electrometrin, a new ouabain receptor protein, isolated from cat cardiac ventricular muscle

• Published in: Japanese Journal of Pharmacology 1992, Vol.58 (suppl.1), p.188-188
• Main Authors: Fujino, Sumiko, Fujino, Masako, Satoh, Kumi, Nakai, Tohru
• Format: Article
• Language: English
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)49064-1

We already reported that electrometrin, a new ouabain receptor protein, which has a high affinity for ouabain, phenylglyoxal(PGO) and concanavalin A (Con A), as solubilized from transverse tubule membrane-junctional SR complexes (TTM-JSR) in cat cardiac ventricular muscle 1). To clarify the mechanisms of ouabain potentiation and the excitation-contraction (E-C) coupling process in the muscle we performed a series of experiments and obtained the following results：The monoclonal antibody against the protein inhibited specifically the E-C coupling process and intracellular calcium transients in the muscle. Immunohistochemical electron microscopic studies showed that the electrometrin localized on the T tubule membrane against the bead which occupies the TTM-JSR gap. Typical electron micrographs by rotary shadowing technique showed that the electrometrin molecule had a globular head and a tail. Effects of ouabain, PGO and Con A on the ultrafine structure of electrometrin were observed. 1)Experientia 45, 467 (1989).