ATP-gated P2X2 channels undergo permeability changes through a process that is incompletely understood. In the present study, we used fluorescence resonance energy transfer (FRET) and electrophysiology to measure cytosolic gating motions in P2X2 channels as they enter a state with increased permeability. P2X2 channels underwent permeability changes with a time course that was similar to decreas...

Two physicochemically and metabolically separate pools of ferritin, namely cytosolic ferritin and lipid-associated ferritin, are present in the livers of guinea pigs. In this paper we establish that the iron content of cytosolic ferritin is dependent on and linearly related to ascorbic acid concentration, whereas changes in concentration of this vitamin do not affect the iron content of lipid-a...

To better understand the relation between cell calcium and exocytotic secretion, a quantitative dependence of adrenal catecholamine secretion on cytosolic free calcium has been determined for isolated, intact, bovine chromaffin cells, using the fluorescent probe Quin-2. The cells required a threshold of 250-300 nM cytosolic calcium to be reached before detectable secretion occurred and half-max...

One important goal in cardiology is to prevent necrotic cell death in the heart. Necrotic cell death attracts neutrophils and monocytes into the injured myocardium. The consequences are fibrosis, remodelling and cardiac failure. The renin-angiotensin system promotes the development of cardiac failure. Recently, alternative renin transcripts have been identified lacking the signal sequence for a...

Increases in cytosolic [Ca(2+)] evoked by trains of action potentials (20-100 Hz) were recorded from mouse and lizard motor nerve terminals filled with a low-affinity fluorescent indicator, Oregon Green BAPTA 5N. In mouse terminals at near-physiological temperatures (30-38 degrees C), trains of action potentials at 25-100 Hz elicited increases in cytosolic [Ca(2+)] that stabilized at plateau le...

Niisato, Naomi, Douglas C. Eaton, and Yoshinori Marunaka. Involvement of cytosolic Cl in osmoregulation of -ENaC gene expression. Am J Physiol Renal Physiol 287: F932–F939, 2004. First published August 10, 2004; doi:10.1152/ajprenal.00131.2004.—Hypotonicity stimulates transepithelial Na reabsorption in renal A6 cells, but the mechanism for this stimulation is not fully understood. In the presen...

Cytosolic free NAD/NADH ratio is fundamentally important in maintaining cellular redox homeostasis but current techniques cannot distinguish between protein-bound and free NAD/NADH. Williamson et al reported a method to estimate this ratio by cytosolic lactate/pyruvate (L/P) based on the principle of chemical equilibrium. Numerous studies used L/P ratio to estimate the cytosolic free NAD/NADH r...

A cytosolic retinoic acid-binding (RAB) protein that sediments specifically as a 2S component on sucrose density gradients was detected in the mammary glands of virgin, pregnant and lactating rats. Mammary cytosol from pregnant rats contained significantly higher concentrations of cytosolic RAB protein than did cytosol from either virgin or lactating rats. The glands of pregnant animals exhibit...

Changes in cytosolic free calcium concentration during myocardial ischemia were measured by 19F NMR in 5FBAPTA-loaded perfused rat hearts. The hearts were perfused with Krebs-Henseleit buffer containing 5 microM of the acetoxymethyl ester of 5FBAPTA, which was hydrolyzed by cytosolic esterases to achieve cytosolic concentrations of 5FBAPTA of 0.12 to 0.65 mM. Cytosolic free calcium concentratio...

Abstract In human cells, one third of all polypeptides enter the secretory pathway at ER. This process involves N-terminal signal peptides or internal transmembrane helices in precursors and hundred cytosolic ER proteins, which facilitate their import processing. past fifty years four pathways for targeting to Sec61 channel plus various allosteric effectors supporting stand alone membrane prote...