Toward a Model for Activation of Orai Channel.

iScience

Institute for Computational Molecular Science, Temple University, Philadelphia, PA 19122, USA. Electronic address:

Published: June 2019

Store-operated calcium release-activated calcium (CRAC) channels mediate a variety of cellular signaling functions. The CRAC channel pore-forming protein, Orai1, is a hexamer arranged with 3-fold symmetry. Despite its importance in moving Ca ions into cells, a detailed mechanistic understanding of Orai1 activation is lacking. Herein, a working model is proposed for the putative open state of Orai from Drosophila melanogaster (dOrai), which involves a "twist-to-open" gating mechanism. The proposed model is supported by energetic, structural, and experimental evidence. Fluorescent imaging demonstrates that each subunit on the intracellular side of the pore is inherently strongly cross-linked, which is important for coupling to STIM1, the pore activator, and graded activation of the Orai1 channel. The proposed model thus paves the way for understanding key aspects of calcium signaling at a molecular level.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6579751PMC
http://dx.doi.org/10.1016/j.isci.2019.05.041DOI Listing

Publication Analysis

Top Keywords

proposed model
8
model
4
model activation
4
activation orai
4
orai channel
4
channel store-operated
4
store-operated calcium
4
calcium release-activated
4
release-activated calcium
4
calcium crac
4

Similar Publications

Vascular HIF2 Signaling Prevents Cardiomegaly, Alveolar Congestion, and Capillary Remodeling During Chronic Hypoxia.

Arterioscler Thromb Vasc Biol

January 2025

Metabolic and Immune Diseases Department, Biomedical Research Institute Sols-Morreale (IIBM), National Research Council (CSIC), Autonoma University of Madrid, Spain (T.A.-G., S.M.-T., R.C.-M., S.U.-B., S.M.-P.).

Background: Hypoxia is associated with the onset of cardiovascular diseases including cardiac hypertrophy and pulmonary hypertension. HIF2 (hypoxia-inducible factor 2) signaling in the endothelium mediates pulmonary arterial remodeling and subsequent elevation of the right ventricular systolic pressure during chronic hypoxia. Thus, novel therapeutic opportunities for pulmonary hypertension based on specific HIF2 inhibitors have been proposed.

View Article and Find Full Text PDF

While maternal mortality decreased during the Millennium Development Goals era, it remains unacceptably high, with stagnation in reductions possible due to shocks such as COVID-19. Most women in low- and middle-income countries already receive antenatal care and over half give birth in health facilities. In cities, use of health facilities for childbirth is near universal (>90%).

View Article and Find Full Text PDF

Semiparametric estimator for the covariate-specific receiver operating characteristic curve.

Stat Methods Med Res

January 2025

CITMAga and Department of Statistics and Operations Research, Universidade de Vigo, Vigo, Galicia, Spain.

The study of the predictive ability of a marker is mainly based on the accuracy measures provided by the so-called confusion matrix. Besides, the area under the receiver operating characteristic curve has become a popular index for summarizing the overall accuracy of a marker. However, the nature of the relationship between the marker and the outcome, and the role that potential confounders play in this relationship could be fundamental in order to extrapolate the observed results.

View Article and Find Full Text PDF

Clinical trials (CTs) often suffer from small sample sizes due to limited budgets and patient enrollment challenges. Using historical data for the CT data analysis may boost statistical power and reduce the required sample size. Existing methods on borrowing information from historical data with right-censored outcomes did not consider matching between historical data and CT data to reduce the heterogeneity.

View Article and Find Full Text PDF

A recent study design for clinical trials with small sample sizes is the small n, sequential, multiple assignment, randomized trial (snSMART). An snSMART design has been previously proposed to compare the efficacy of two dose levels versus placebo. In such a trial, participants are initially randomized to receive either low dose, high dose or placebo in stage 1.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!