The use of the indicator fluo-5N to measure sarcoplasmic reticulum calcium in single muscle fibres of the cane toad.
AuthorsKabbara AA, Allen DG
JournalJ Physiol
PubMed ID11432994
'1. Single fibres from the lumbrical muscles of the cane toad (Bufo marinus) were incubated in fluo-5N AM for 2 h at 35 degrees C in order to load the indicator into the sarcoplasmic reticulum. Fluo-5N is a low-affinity calcium indicator (K(Ca) 90 microM). Successful sarcoplasmic reticulum (SR) loading was ... More
Cardiac alternans do not rely on diastolic sarcoplasmic reticulum calcium content fluctuations.
AuthorsPicht E, DeSantiago J, Blatter LA, Bers DM,
JournalCirc Res
PubMed ID16946134
'Cardiac alternans are thought to be a precursor to life-threatening arrhythmias. Previous studies suggested that alterations in sarcoplasmic reticulum (SR) Ca2+ content are either causative or not associated with myocyte Ca2+ alternans. However, those studies used indirect measures of SR Ca2+. Here we used direct continuous measurement of intra-SR free ... More
Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons.
AuthorsBannai H, Inoue T, Nakayama T, Hattori M, Mikoshiba K
JournalJ Cell Sci
PubMed ID14676272
'Although spatially restricted Ca2+ release from the endoplasmic reticulum (ER) through intracellular Ca2+ channels plays important roles in various neuronal activities, the accurate distribution and dynamics of ER in the dendrite of living neurons still remain unknown. To elucidate these, we expressed fluorescent protein-tagged ER proteins in cultured mouse hippocampal ... More
Ca2+ blinks: rapid nanoscopic store calcium signaling.
AuthorsBrochet DX, Yang D, Di Maio A, Lederer WJ, Franzini-Armstrong C, Cheng H
JournalProc Natl Acad Sci U S A
PubMed ID15710901
'Luminal Ca(2+) in the endoplasmic and sarcoplasmic reticulum (ER/SR) plays an important role in regulating vital biological processes, including store-operated capacitative Ca(2+) entry, Ca(2+)-induced Ca(2+) release, and ER/SR stress-mediated cell death. We report rapid and substantial decreases in luminal [Ca(2+)], called "Ca(2+) blinks," within nanometer-sized stores (the junctional cisternae of ... More
Sulfhydryl oxidation overrides Mg(2+) inhibition of calcium-induced calcium release in skeletal muscle triads.
AuthorsDonoso P, Aracena P, Hidalgo C
JournalBiophys J
PubMed ID10866954
'We studied the effect of oxidation of sulfhydryl (SH) residues on the inhibition by Mg(2+) of calcium-induced calcium release (CICR) in triad-enriched sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle. Vesicles were either passively or actively loaded with calcium before eliciting CICR by dilution at pCa 4.6-4.4 in the presence ... More
Termination of cardiac Ca2+ sparks: role of intra-SR [Ca2+], release flux, and intra-SR Ca2+ diffusion.
AuthorsZima AV, Picht E, Bers DM, Blatter LA,
JournalCirc Res
PubMed ID18787194
'Ca(2+) release from cardiac sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) is regulated by dyadic cleft [Ca(2+)] and intra-SR free [Ca(2+)] ([Ca(2+)](SR)). Robust SR Ca(2+) release termination is important for stable excitation-contraction coupling, and partial [Ca(2+)](SR) depletion may contribute to release termination. Here, we investigated the regulation of SR Ca(2+) ... More
Modulation of SR Ca release by luminal Ca and calsequestrin in cardiac myocytes: effects of CASQ2 mutations linked to sudden cardiac death.
AuthorsTerentyev D, Kubalova Z, Valle G, Nori A, Vedamoorthyrao S, Terentyeva R, Viatchenko-Karpinski S, Bers DM, Williams SC, Volpe P, Gyorke S,
JournalBiophys J
PubMed ID18469084
Cardiac calsequestrin (CASQ2) is an intrasarcoplasmic reticulum (SR) low-affinity Ca-binding protein, with mutations that are associated with catecholamine-induced polymorphic ventricular tachycardia (CPVT). To better understand how CASQ2 mutants cause CPVT, we expressed two CPVT-linked CASQ2 mutants, a truncated protein (at G112+5X, CASQ2(DEL)) or CASQ2 containing a point mutation (CASQ2(R33Q)), in ... More
IP3-dependent nuclear Ca2+ signalling in the mammalian heart.
AuthorsZima AV, Bare DJ, Mignery GA, Blatter LA,
JournalJ Physiol
PubMed ID17761776
In cardiac myocytes the type-2 inositol 1,4,5-trisphosphate receptor (IP(3)R2) is the predominant isoform expressed. The IP(3)R2 channel is localized to the SR and to the nuclear envelope. We studied IP(3)-dependent nuclear Ca(2+) signals ([Ca(2+)](Nuc)) in permeabilized atrial myocytes and in isolated cardiac nuclei. In permeabilized myocytes IP(3) (20 microm) and ... More
FM dyes enter via a store-operated calcium channel and modify calcium signaling of cultured astrocytes.
AuthorsLi D, Hérault K, Oheim M, Ropert N,
JournalProc Natl Acad Sci U S A
PubMed ID20007370
The amphiphilic fluorescent styryl pyridinium dyes FM1-43 and FM4-64 are used to probe activity-dependent synaptic vesicle cycling in neurons. Cultured astrocytes can internalize FM1-43 and FM4-64 inside vesicles but their uptake is insensitive to the elevation of cytosolic calcium (Ca(2+)) concentration and the underlying mechanism remains unclear. Here we used ... More
NAADP, cADPR and IP3 all release Ca2+ from the endoplasmic reticulum and an acidic store in the secretory granule area.
AuthorsGerasimenko JV, Sherwood M, Tepikin AV, Petersen OH, Gerasimenko OV
JournalJ Cell Sci
PubMed ID16410548
Inositol trisphosphate and cyclic ADP-ribose release Ca2+ from the endoplasmic reticulum via inositol trisphosphate and ryanodine receptors, respectively. By contrast, nicotinic acid adenine dinucleotide phosphate may activate a novel Ca2+ channel in an acid compartment. We show, in two-photon permeabilized pancreatic acinar cells, that the three messengers tested could each ... More
Sustained overexpression of IGF-1 prevents age-dependent decrease in charge movement and intracellular Ca(2+) in mouse skeletal muscle.
AuthorsWang ZM, Messi ML, Delbono O
JournalBiophys J
PubMed ID11867450
In this work we tested the hypothesis that transgenic sustained overexpression of IGF-1 prevents age-dependent decreases in charge movement and intracellular Ca(2+) in skeletal muscle fibers. To this end, short flexor digitorum brevis (FDB) muscle fibers from 5-7- and 21-24-month-old FVB (wild-type) and S1S2 (IGF-1 transgenic) mice were studied. Fibers ... More
Screening assays for the mitochondrial permeability transition using a fluorescence multiwell plate reader.
AuthorsBlattner JR, He L, Lemasters JJ
JournalAnal Biochem
PubMed ID11488625
Opening of permeability transition (PT) pores in the mitochondrial inner membrane causes the mitochondrial permeability transition (MPT) and leads to mitochondrial swelling, membrane depolarization, and release of intramitochondrial solutes. Here, our aim was to develop high-throughput assays using a fluorescence plate reader to screen potential inducers and blockers of the ... More
Effects of electrical shocks on Cai2+ and Vm in myocyte cultures.
AuthorsFast VG, Cheek ER, Pollard AE, Ideker RE
JournalCirc Res
PubMed ID15155528
Changes in intracellular calcium concentration (DeltaCa(i)2+) induced by electrical shocks may play an important role in defibrillation, but high-resolution DeltaCa(i)2+ measurements in a multicellular cardiac tissue and their relationship to corresponding Vm changes (DeltaVm) are lacking. Here, we measured shock-induced DeltaCa(i)2+ and DeltaV(m) in geometrically defined myocyte cultures. Cell strands ... More
Protein kinase CK2 impact on intracellular calcium homeostasis in prostate cancer.
Authors
JournalMol Cell Biochem
PubMed ID32436081
CMYA5 establishes cardiac dyad architecture and positioning.