Related Experiment Videos
The extracellular calcium-sensing receptor dimerizes through multiple types of intermolecular interactions
1Endocrine-Hypertension Division and Membrane Biology Program, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
The Journal of Biological Chemistry
|November 9, 2000
Summary
The extracellular calcium-sensing receptor (CaR) dimerizes through both covalent disulfide bonds and noncovalent interactions. Cysteine residues are not essential for CaR dimerization or function, suggesting alternative dimerization mechanisms.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Endocrinology
Background:
- The extracellular calcium-sensing receptor (CaR) is a G protein-coupled receptor crucial for calcium homeostasis.
- CaR forms disulfide-linked dimers via extracellular cysteine residues, which are thought to have functional implications.
Purpose of the Study:
- To identify essential disulfide linkages for CaR dimerization.
- To determine if these disulfide bonds are required for CaR functional interactions.
Main Methods:
- Site-directed mutagenesis to alter cysteine residues.
- Chemical cross-linking assays.
- Immunoprecipitation of CaR dimers.
- Reconstitution of CaR-mediated signaling in cotransfected cells.
Main Results:
- Cys(129) and Cys(131) play key roles in CaR dimerization.
- CaRs lacking Cys(129) and Cys(131) still form dimers on the cell surface.
- Covalent disulfide linkage is not required for functional interactions between CaR monomers.
Conclusions:
- CaR dimerization involves both covalent disulfide bonds and noncovalent interactions.
- Noncovalent interactions are sufficient for CaR dimerization and functional signaling.
- The CaR possesses distinct motifs for covalent and noncovalent dimerization and function.