*Correspondence to: H. Llewelyn Roderick; Email: [email protected] Cardiac hypertrophy is associated with profound remodeling of Ca signaling pathways. During the early, compensated stages of hypertrophy, Ca fluxes may be enhanced to facilitate greater contraction, whereas as the hypertrophic heart decompensates, Ca homeostatic mechanisms are dysregulated leading to decreased contra...

The repetitive spiking of free cytosolic [Ca 2 1 ] ([Ca 2 1 ] i ) during hormonal activation of hepatocytes depends on the activation and subsequent inactivation of InsP 3 -evoked Ca 2 1 release. The kinetics of both processes were studied with flash photolytic release of InsP 3 and time resolved measurements of [Ca 2 1 ] i in single cells. InsP 3 evoked Ca 2 1 flux into the cytosol was measure...

Inositol-1,4,5-trisphosphate (InsP(3))-mediated calcium signals represent an important mechanism for transmitting external stimuli to the cell. However, information about intracellular spatial patterns of InsP(3) itself is not generally available. In particular, it has not been determined how the interplay of InsP(3) generation, diffusion, and degradation within complex cellular geometries can ...

To examine the effect of inclusion insoluble nonstarch polysaccharides (iNSP) in weaned diets on postweaning piglet performance, intestinal activity, and microbial composition 2 experiments were designed. In Exp. 1, 180 piglets were weaned at 28 d of age and divided over 3 treatments: positive control (PC; highly digestible protein), negative control (NC; standard cereal-based diet), and an exp...

Various biochemical signals are implicated in Arabidopsis wound signalling, including jasmonic acid (JA), salicylic acid, auxin, and Ca2+. Here, we report on cross-talk of phytohormones with phosphoinositide signals not previously implicated in plant wound responses. Within 30 min of mechanical wounding of Arabidopsis rosette-leaves, the levels of the lipid-derived soluble inositolpolyphosphate...

It has been proposed that the inositol 1,4,5-trisphosphate receptor (InsP(3)R) type III acts as a trigger for InsP(3)-mediated calcium (Ca(2+)) signaling, because this InsP(3) isoform lacks feedback inhibition by cytosolic Ca(2+). We tested this hypothesis in RIN-m5F cells, which express predominantly the type III receptor. Extracellular ATP increases Ca(2+) in these cells, and we found that th...

Among rat peripheral tissues examined, Ins(1,4,5)P(3) receptor binding is highest in the vas deferens, with levels about 25% of those of the cerebellum. We have purified the InsP(3) receptor binding protein from rat vas deferens membranes 600-fold. The purified protein displays a single 260 kDa band on SDS/PAGE, and the native protein has an apparent molecular mass of 1000 kDa, the same as in c...

Combining experimental data and computer modeling, Fink et al. (page 929) demonstrate that cellular geometry is important in the spatiotemporal control of intracellular signaling. The researchers examined the dynamics of inositol-1,4,5-trisphosphate (InsP 3 )-mediated calcium signaling in neuroblastoma cells with complex morphology, and also simulated InsP 3 signaling in a computer model called...

Cardiac hypertrophy is a growth response of the heart to increased hemodynamic demand or damage. Accompanying this heart enlargement is a remodeling of Ca(2+) signaling. Due to its fundamental role in controlling cardiomyocyte contraction during every heartbeat, modifications in Ca(2+) fluxes significantly impact on cardiac output and facilitate the development of arrhythmias. Using cardiomyocy...

Smooth muscle cells respond to InsP(3)-generating (sarcolemma-acting) neurotransmitters and hormones by releasing Ca(2+) from the internal store. However, the release of Ca(2+) does not occur uniformly throughout the cytoplasm but often into a localized area before being transmitted to other regions of the cell in the form of Ca(2+) waves and oscillations to actively spread information within a...