Adenine nucleotides stimulate oxidation-induced calcium efflux from sarcoplasmic reticulum vesicles.
Micromolar concentrations of copper (Cu2+) and cysteine induce rapid efflux of calcium from sarcoplasmic reticulum (SR) vesicles. This effect appears to be due to a Cu2+-catalyzed oxidation of the added cysteine to a critical sulfhydryl group on the release protein from sarcoplasmic reticulum (J. L. Trimm, G. Salama, and J. J. Abramson (1986) J. Biol. Chem. 261, 16092-16098). The data presented here indicate that adenine nucleotides synergistically stimulate copper/cysteine (oxidation)-induced calcium efflux from SR vesicles. The order of effectiveness in stimulating calcium efflux is ATP greater than AMP-PCP greater than cAMP greater than AMP greater than adenine approximately NAD approximately NADH. Non-adenine-containing nucleotides such as GTP, CTP, UTP, and ITP and the high energy phosphate compound, acetyl phosphate, were ineffective in stimulating oxidation-induced calcium efflux. The relative effectiveness of various adenine nucleotides in stimulating calcium-induced calcium efflux and oxidation-induced calcium efflux are identical, suggesting that a common mode of action is involved when calcium release is triggered by either method. The stimulatory effect of the adenine nucleotides on oxidation-induced efflux is independent of external magnesium concentration and independent of the magnesium gradient across the SR membrane.
Stuart
J
J
Department of Chemistry, Portland State University, Oregon 97207.
Abramson
J J
JJ
D000227:Adenine Nucleotides / Q000494:pharmacology*; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D009132:Muscles / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D000227:Adenine Nucleotides; D007473:Ion Channels; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D000249:Adenosine Monophosphate; D003300:Copper; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D008274:Magnesium; D003545:Cysteine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002118:Calcium