G protein-coupled receptor dimeric complex

Definition

Target type: cellularcomponent

A protein complex that contains two G protein-coupled receptors. [GOC:al, GOC:bf, PMID:10713101]

The cellular component of a G protein-coupled receptor (GPCR) dimeric complex is a complex assembly of proteins that plays a crucial role in signal transduction. It involves two GPCRs interacting with each other, forming a dimer, and this dimer can associate with other proteins, such as G proteins, arrestins, and other signaling molecules. The specific arrangement and interactions within the complex are influenced by various factors, including the type of GPCRs involved, the presence of ligands, and the cellular context.

Here's a detailed breakdown of the cellular component:

**1. GPCR Dimer:**
* Two GPCRs associate through various interactions, including transmembrane domain interactions, extracellular loop interactions, and intracellular loop interactions.
* Dimerization can occur through homodimers (two identical GPCRs) or heterodimers (two different GPCRs).
* The dimerization process is often regulated by factors like ligand binding, phosphorylation, and interactions with other proteins.

**2. G protein:**
* G proteins are heterotrimeric proteins composed of alpha, beta, and gamma subunits.
* Upon GPCR activation, the alpha subunit exchanges GDP for GTP, leading to its dissociation from the beta-gamma dimer.
* The activated alpha subunit and beta-gamma dimer then interact with downstream effectors, initiating signaling cascades.

**3. Arrestins:**
* Arrestins are adaptor proteins that bind to activated GPCRs, leading to receptor desensitization and internalization.
* Arrestins can also recruit other signaling molecules to the complex, influencing downstream pathways.

**4. Other Signaling Molecules:**
* The GPCR dimeric complex can interact with various other signaling molecules, such as kinases, phosphatases, and scaffolding proteins.
* These interactions contribute to the complex's signaling versatility and ability to fine-tune cellular responses.

**5. Lipid Rafts:**
* GPCR dimeric complexes are often enriched in lipid rafts, specialized membrane microdomains enriched in cholesterol and sphingolipids.
* Lipid rafts provide a platform for GPCR clustering, enhancing signaling efficiency and promoting interactions with other signaling molecules.

In summary, the cellular component of a GPCR dimeric complex is a dynamic assembly of proteins that plays a central role in signal transduction. Its composition and interactions are finely tuned, allowing for precise control of cellular responses. The complex's involvement in diverse signaling pathways highlights its importance in regulating various physiological processes.'
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Proteins (1)

Compounds (49)