The sarcoplasmic reticulum Ca2+ pump: inhibition by thapsigargin and enhancement by adenovirus-mediated gene transfer.
The role of the sarcoplasmic reticulum Ca2+ pump in the excitation-contraction coupling of cardiac muscle fibers was evaluated in experiments on SR ATPase inhibition with thapsigargin or, alternatively, on Ca2+ pump enhancement by SR ATPase transgenic expression. We found that thapsigargin, a highly specific and potent inhibitor of the SR ATPase, produces a strong reduction of cytosolic Ca2+ transient and contractile activation in neonatal rat myocytes, in the absence of any other functional effect. On the other hand, Ca2+ pump enhancement by ATPase transgenic expression affects dramatically Ca2+ transient and twitches, resulting in shorter duration and more rapid decay rates. Of particular interest is gene transfer mediated by recombinant adenovirus vectors under control of a cell-specific promoter, resulting in transgenic expression of all myocytes in culture, and no expression in fibroblasts.
Inesi
G
G
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore 21201, USA.
Wade
R
R
Rogers
T
T
D000256:Adenoviridae; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D005822:Genetic Vectors; D006321:Heart / Q000502:physiology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009200:Myocardial Contraction; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D017433:Protein Structure, Secondary; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D019284:Thapsigargin / Q000494:pharmacology*
D019284:Thapsigargin; D000252:Calcium-Transporting ATPases