Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Ryanodine receptor (RyR) Ca2+ channels in the sarcoplasmic reticulum (SR) of skeletal muscle are regulated by the 12 kDa FK506- (or rapamycin-) binding protein (FKBP12). Rapamycin can also activate RyR channels with FKBP12 removed, suggesting that compounds with macrocyclic lactone ring structures can directly activate RyRs. Here we tested this hypothesis using two other macrocyclic lactone compounds, ivermectin and midecamycin. 2. Rabbit skeletal RyRs were examined in lipid bilayers. Ivermectin (cis, 0.66-40 microM) activated six of eight native, four of four control-incubated and eleven of eleven FKBP12-'stripped' RyR channels. Midecamycin (cis, 10-30 microM) activated three of four single native channels, six of eight control-incubated channels and six of seven FKBP12-stripped channels. Activity declined when either drug was washed out. 3. Neither ivermectin nor midecamycin removed FKBP12 from RyRs. Western blots of terminal cisternae (TC), incubated for 15 min at 37 C with 40 microM ivermectin or midecamycin, showed normal amounts of FKBP12. In contrast, no FKBP12 was detected after incubation with 40 microM rapamycin. 4. Ivermectin reduced Ca2+ uptake by the SR Ca2+-Mg2+-ATPase. Ca2+ uptake by TC fell to approximately 40% in the presence of ivermectin (10 microM), both with and without 10 microM Ruthenium Red. Ca2+ uptake by longitudinal SR also fell to approximately 40% with 10 microM ivermectin. Midecamycin (10 microM) reduced Ca2+ uptake by TC vesicles to approximately 76% without Ruthenium Red and to approximately 90 % with Ruthenium Red. 5. The rate of rise of extravesicular [Ca2+] increased approximately 2-fold when 10 microM ivermectin was added to TC vesicles that had been partially loaded with Ca2+ and then Ca2+ uptake blocked by 200 nM thapsigargin. Ivermectin also potentiated caffeine-induced Ca2+ release to approximately 140% of control. These increases in Ca2+ release were not seen with midecamycin. 6. Ivermectin, but not midecamycin, reversibly reduced Ca2+ loading in four of six skinned rat extensor digitorum longus (EDL) fibres to approximately 90%, and reversibly increased submaximal caffeine-induced contraction in five of eight fibres by approximately 110% of control. Neither ivermectin nor midecamycin altered twitch or tetanic tension in intact EDL muscle fibres within 20 min of drug addition. 7. The results confirm the hypothesis that compounds with a macrocyclic lactone ring structure can directly activate RyRs. Unexpectedly, ivermectin also reduced Ca2+ uptake into the SR. These effects of ivermectin on SR Ca2+ handling may explain some effects of the macrolide drugs on mammals.
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PMID:Effects of ivermectin and midecamycin on ryanodine receptors and the Ca2+-ATPase in sarcoplasmic reticulum of rabbit and rat skeletal muscle. 985 16

Drug-inducible recombination based on flippase (FLP) is frequently used in animal models and in transgenic cell lines to initiate or to abrogate gene expression. Although the system is highly efficient, functional gene analyses depend on the availability of suitable animal models. In contrast, lentiviral vectors are readily available and versatile tools for the transfer of genetic information into a wide variety of target cells, and can be produced at high titer in a timely manner. To combine the advantages of both approaches, we generated a tight, drug-controlled FLP recombinase consisting of a 5' FKBP12 derived conditional destruction domain and a 3' estrogen receptor ligand binding (ERT2) domain. We successfully constructed lentiviral vectors expressing drug-controlled FLP in combination with a fluorescent reporter for recombination of FLP recognition target (FRT) sites located in trans as well as with target alleles located in cis (all-in-one configuration). In this chapter, we describe the design of the drug controlled FLP recombinase, the construction of molecular switches consisting of FLP expressing lentiviral vectors for inducible recombination of target sites located in cis and in trans, as well as the details for the characterization of lentiviral FLP vectors in cell lines.
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PMID:Development of Inducible Molecular Switches Based on All-in-One Lentiviral Vectors Equipped with Drug Controlled FLP Recombinase. 2731 70