G protein-coupled UDP receptor activity

Definition

Target type: molecularfunction

Combining with a nucleotide and transmitting the signal to a heterotrimeric G-protein complex to initiate a change in cell activity, activated by UDP. [GOC:mah]

G protein-coupled UDP receptors (GPCRs) are integral membrane proteins that play a crucial role in cellular signaling. These receptors bind UDP, a ubiquitous nucleotide, and initiate downstream signaling cascades through the activation of G proteins. The molecular function of G protein-coupled UDP receptor activity can be described in several key steps:

1. **Ligand Binding:** UDP binds to the extracellular domain of the receptor, triggering a conformational change in the protein. This conformational change is essential for the subsequent activation of G proteins.

2. **G Protein Coupling:** Upon UDP binding, the receptor interacts with and activates heterotrimeric G proteins. These proteins are composed of three subunits: alpha (α), beta (β), and gamma (γ). The α subunit is responsible for binding GDP in its inactive state.

3. **GDP/GTP Exchange:** The activated receptor facilitates the exchange of GDP for GTP on the α subunit of the G protein. This exchange event marks the activation of the α subunit, which subsequently dissociates from the βγ subunits.

4. **Signal Transduction:** The activated α subunit, bound to GTP, interacts with downstream effector proteins, such as adenylyl cyclase, phospholipase C, or ion channels. This interaction initiates a cascade of intracellular signaling events, leading to diverse cellular responses.

5. **GTP Hydrolysis and Deactivation:** The α subunit has intrinsic GTPase activity, which eventually hydrolyzes GTP to GDP. This hydrolysis event inactivates the α subunit, allowing it to reassociate with the βγ subunits and return the G protein to its inactive state.

6. **Receptor Desensitization:** After prolonged exposure to UDP, the receptor can undergo desensitization, reducing its signaling activity. This desensitization mechanism involves phosphorylation of the receptor by kinases and the binding of arrestin proteins.

In summary, the molecular function of G protein-coupled UDP receptor activity involves a series of events, from ligand binding to signal transduction and deactivation, ultimately leading to the modulation of cellular processes. This intricate signaling pathway plays a vital role in various physiological functions, including inflammation, immune responses, and neuronal activity.'
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Proteins (2)

Compounds (19)