Related Experiment Video
Updated: Jul 19, 2026
12:30
Monitoring ER/SR Calcium Release with the Targeted Ca2+ Sensor CatchER+
Published on: May 19, 2017
The calcium-sensing receptor (CaR) and its disorders
1Endocrine-Hypertension Division and Membrane Biology Program, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. embrown@rics.bwh.harvard.edu
Hormones (Athens, Greece)
|October 5, 2006
Summary
The calcium-sensing receptor (CaR) regulates extracellular calcium levels, crucial for bodily functions. Mutations in CaR cause calcium disorders, highlighting its vital role in mineral metabolism.
Area of Science:
- Biochemistry
- Endocrinology
- Molecular Biology
Background:
- Extracellular calcium (Ca(2+o)) homeostasis is vital for cellular functions.
- Parathyroid cells and other tissues maintain stable Ca(2+o) levels.
- The precise mechanism of Ca(2+o) sensing was previously unclear.
Purpose of the Study:
- To elucidate the mechanism by which parathyroid cells sense Ca(2+o).
- To identify the molecular basis of calcium homeostasis regulation.
- To understand the role of extracellular calcium as an informational signal.
Main Methods:
- Molecular cloning and characterization of the calcium-sensing receptor (CaR).
- Analysis of CaR mutations in inherited human disorders.
- Investigating the physiological roles of CaR in mineral ion metabolism.
Main Results:
- The G protein-coupled CaR was identified as the primary sensor for Ca(2+o).
- CaR mutations lead to hypercalcemia (activating mutations) and hypocalcemia (inactivating mutations).
- Extracellular calcium ions function as a critical informational signal.
Conclusions:
- The CaR is essential for maintaining mineral ion metabolism and Ca(2+o) homeostasis.
- Calcimimetics (CaR activators) show promise for treating hyperparathyroidism.
- Calcilytics (CaR antagonists) may offer therapeutic benefits in specific clinical contexts.
Related Concept Videos
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:21Skeleton and Calcium Homeostasis
Calcium is not only the most abundant mineral in bone but also the most abundant mineral in the human body. Calcium ions are needed for bone mineralization, tooth health, heart rate regulation and strength of contraction, blood coagulation, the contraction of smooth and skeletal muscle cells, and the regulation of nerve impulse conduction. The average calcium level in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo or hypercalcemia.
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:25Imaging Studies for Cardiovascular System VI: Calcium -Scoring CT
Calcium-Scoring CT ScanA calcium-scoring CT scan, also known as coronary artery calcium (CAC) scan, detects calcium deposits in the coronary arteries. This test assesses the risk of coronary artery disease (CAD), which can lead to cardiovascular events such as angina, heart failure, and sudden cardiac arrest.A calcium-scoring CT scan is generally recommended for individuals at intermediate risk of CAD without symptoms. It includes:Men aged 40-75 and women aged 50-75: Especially those with a...
00:51Synthesis and Functions of Calcitonin
Calcitonin, a vital polypeptide hormone, regulates calcium levels within body fluids. It is released by the parafollicular cells, also known as C cells, situated in the follicular epithelium of the thyroid gland. Calcitonin responds to fluctuations in blood calcium levels and the influence of gastrointestinal hormones like gastrin and cholecystokinin.
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...