Calcium-dependent phospholipid binding proteins associated with the membranes of rabbit skeletal muscle.
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.
Melgunov
V I
VI
Department of Molecular Biology, School of Biology, M.V. Lomonosov State University, Moscow, USSR.
Mamedova
N A
NA
Akimova
E I
EI
Adzhimolaev
T A
TA
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D002352:Carrier Proteins / Q000032:analysis*; D004533:Egtazic Acid; D004591:Electrophoresis, Polyacrylamide Gel; D007425:Intracellular Membranes / Q000032:analysis; D008081:Liposomes / Q000032:analysis; D008563:Membrane Lipids / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis*; D009124:Muscle Proteins / Q000032:analysis*; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids / Q000302:isolation & purification; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000032:analysis; D012995:Solubility
D002352:Carrier Proteins; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D009124:Muscle Proteins; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; D004533:Egtazic Acid; D002118:Calcium