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Biochemical assays reveal how three proteins fit together to form the channel that controls the flow of calcium ions into mitochondria.

1. The effects of calcium on the motility of different preparations of flagella from Crithidia oncopelti were studied using stroboscopic and high-speed cine photographic techniques. 2. By varying the concentration of calcium in suspensions of chemically treated samples of the organism it was found that changes occurred in bend shape, wave direction and frequency. 3. Waves on the flagellum of th...

A neuron's record of its previous activity underlies animal memory. A new study reveals a role for the release of calcium ions from intracellular stores in mediating spatially compartmentalized memory of the activity history of a neuron.

During the past decades, many different fluorescent indicators have been developed for measuring intracellular ion concentrations. Of particular interest are fluorescent calcium indicators because of the fundamental role of Ca in various cellular processes such as contraction, secretion, and gene activation. For a quantitative understanding of the physiological roles of Ca, fluorescence signals...

Experiments were performed on the lobster giant axon to determine the relation between intracellular spike amplitude and external calcium ion concentration. Action potential decline in low external calcium is greatly accelerated by simultaneous removal of external sodium ion. Correlation of the time course of spike decline in low calcium-low sodium solution with the time courses of spike declin...

The Ca(2+)-dependent slow afterhyperpolarization (AHP) is an important determinant of neuronal excitability. Although it is established that modest changes in extracellular pH (pH(o)) modulate the slow AHP, the relative contributions of changes in the priming Ca(2+) signal and intracellular pH (pH(i)) to this effect remain poorly defined. To gain a better understanding of the modulation of the ...

Fura-2 is a popular real-time fluorescent indicator used to image intracellular, free calcium concentrations ([Ca2+]i) in living cells. One difficulty with fura-2-based digital imaging is how to best display the [Ca2+]i information that is acquired. Typically, only the [Ca2+]i as pseudocolor data are displayed, and the localization and intensity of the dye are not presented. This paper describe...

Ion channels are embedded in the lipid bilayer of cell membranes; therefore, it is not surprising that their functions can be modulated by membrane phospholipids and their metabolites. Over the last decade, a number of ion channels—including multiple types of potassium channels, voltage-gated calcium channels, and transient receptor potential channels—have been shown to be modulated by phosphol...

Calcium ions mediate extracellular signals on intracellular processes. The signalling system based on transient rises or oscillations of the cytoplasmic calcium concentration has potential advantages. The relevant mechanisms of intracellular concentration changes include calcium-induced calcium release and calcium dependent inactivation of calcium release. A model has been devised based on thes...