Inositol 1,4,5-tris-phosphate activation of inositol tris-phosphate receptor Ca ²⁺ channel by ligand tuning of Ca ²⁺ inhibition

Abstract

Medical Sciences. In the article "Activation of protein kinase C correlates with a cardioprotective effect of regular ethanol consumption" by Masami Miyamae, Manuel M. Rodriguez, S. Albert Camacho, Ivan Diamond, Daira Mochly-Rosen, and Vincent M. Figueredo, which appeared in number 14, July 7, 1998, of Proc. Natl. Acad. Sci. USA (95, 8262-8267), the following correction should be noted. On page 8264, an incorrect Fig. 1 was printed. The correct figure and its accompanying legend are reproduced below.Neurobiology. In the article "Caspase-1 is activated in neural cells and tissue with amyotrophic lateral sclerosis-associated mutations in copper-zinc superoxide dismutase" by Piera Pasinelli, David R. Borchelt, Megan K. Houseweart, Don W. Cleveland, and Robert H. Brown, Jr., which appeared in number 26, December 22, 1998, of Proc. Natl. Acad. Sci. USA (95, 15763-15768), the following corrections should be noted. An erroneous version of Fig. 6 was published. The lane indicated as G41D represents lumbo-sacral spinal cord extract from G85R transgenic mice. In Fig. 7a, cell viability is expressed as % of untreated cells and not as % of viability. FIG. 1. LVDP prior to 45 min of global ischemia and during reperfusion in four groups of perfused guinea pig hearts (n ϭ 9 for each group): 1, following 8 wk 15% ethanol-derived calories (E); 2, pair-fed controls (‚); 3, following 8 wk of ethanol, before and after 10 mM chelerythrine (F); and 4, pair-fed controls, before and after chelerythrine (s). LVDP recovery is significantly greater in hearts from ethanol-treated animals (P Ͻ 0.05 at each 6-min interval). Chelerythrine abolished ethanol's protective effect on LVDP recovery. Data are presented as mean Ϯ SEM (SEM not included for group 2 but lie well within SEM of groups 3 and 4). Physiology 3330Corrections Proc. Natl. Acad. Sci. USA 96 (1999)

The endoplasmic reticulum gateway to apoptosis by Bcl-XL modulation of the InsP3R

“…When [InsP 3 ] was reduced to 10 nM, channel activity was substantially decreased (P o ~0.02) (Fig. 2b), consistent with the [InsP 3 ] dependence of channel gating 17 , and N A was only ~0.1 (Fig. 2c).…”

“…The pipette solution contained 140 mM KCl, 0.5 mM ATP, 10 mM HEPES, pH 7.1. The free [Ca 2+ ] in all solutions was adjusted to the desired level by the addition of an appropriate Ca 2+ chelator, as described previously 17 . Experiments were performed at room temperature.…”

“…The functional consequences of the interaction of Bcl-X L with the InsP 3 R were explored by recording single InsP 3 R channels in native ER membranes, by patch-clamp electrophysiology of outer membranes of isolated nuclei 17 (Fig. 2a).…”

Ca2+ signaling differentiation during oocyte maturation

“…The saltatory wave relies on the bell-shaped Ca 2þ -dependence of the IP 3 R (Lechleiter and Clapham, 1992). Ca 2þ at low and high concentrations decreases the probability of opening of the IP 3 R and favors opening at intermediate concentrations (Bezprozvanny et al, 1991;Mak et al, 1998). Therefore, assuming even IP 3 distribution, Ca 2þ release at one site produces elevated Ca 2þ concentration in the vicinity of the releasing IP 3 R channels leading to their closing (Fig.…”

Emergence of ion channel modal gating from independent subunit kinetics

“…Under fixed ligand conditions, the type 1 IP 3 R gates in three modes that are characterized by high, intermediate, and low open probability. The within-mode open probabilities are approximately ligand independent, whereas the proportion of time spent in each mode is regulated by the IP 3 and Ca 2+ concentration (7,30), leading to the well-described bell-shaped open probability curve (28,31,32). In contrast to the slow switching between modes, the channel exhibits individual opening and closing events of millisecond durations and responds rapidly to changing ligand concentrations (29).…”