1. Calcium-dependent phospholipid binding proteins associated with the membranes of rabbit skeletal muscle.
- Author
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Melgunov VI, Mamedova NA, Akimova EI, and Adzhimolaev TA
- Subjects
- Animals, Binding Sites drug effects, Egtazic Acid, Electrophoresis, Polyacrylamide Gel, Intracellular Membranes analysis, Liposomes analysis, Membrane Lipids analysis, Phospholipids isolation & purification, Rabbits, Sarcoplasmic Reticulum analysis, Solubility, Calcium pharmacology, Carrier Proteins analysis, Membrane Proteins analysis, Muscle Proteins analysis, Phospholipid Transfer Proteins
- Abstract
By using extraction in the presence of Ca2+ and Triton X-100 and then in the presence of EGTA without detergent, a set of Ca2+-dependent phospholipid binding proteins has been identified in the membranes of transverse tubules (T-tubules) and sarcoplasmic reticulum (SR), isolated from rabbit skeletal muscles. Longitudinal SR, junctional SR and T-tubule membranes yielded about 9, 14 and 3.3 micrograms of EGTA-soluble proteins per 1 mg of membrane protein, respectively. In the presence of 1 mM CaCl2, 68 and 33 kDa proteins of T-tubules and junctional SR as well as 30 kDa protein of T-tubules were shown to bind to liposomes made of 1:1 w/w mixtures of (i) phosphatidylcholine and (ii) phosphatidylserine, phosphatidic acid, or phosphatidyl ethanolamine. In the presence of EGTA, the above-mentioned proteins were mostly found in the supernatants. Binding of the proteins with liposomes consisting of pure phosphatidylcholine was negligible.
- Published
- 1990
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