G protein-coupled UTP 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 UTP. [GOC:mah]

G protein-coupled UTP receptors (UTP-GPCRs) are integral membrane proteins that mediate cellular responses to the nucleotide uridine triphosphate (UTP). These receptors are involved in a wide range of physiological processes, including inflammation, cell proliferation, and smooth muscle contraction.

The molecular function of UTP-GPCR activity involves a complex interplay of events that ultimately leads to the activation of downstream signaling pathways.

1. **Ligand Binding:** UTP binds to the extracellular domain of the receptor, triggering a conformational change in the protein.

2. **G Protein Activation:** This conformational change activates a heterotrimeric G protein, which is composed of alpha, beta, and gamma subunits. The alpha subunit is bound to GDP in its inactive state. Upon receptor activation, the alpha subunit exchanges GDP for GTP, becoming activated.

3. **Signaling Cascade Initiation:** The activated alpha subunit dissociates from the beta and gamma subunits and interacts with downstream effector molecules, such as phospholipase C (PLC).

4. **Second Messenger Production:** PLC catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol trisphosphate (IP3). These second messengers activate protein kinase C (PKC) and release calcium from intracellular stores, respectively.

5. **Cellular Response:** The activation of PKC and calcium signaling pathways leads to a variety of cellular responses, including the activation of transcription factors, the regulation of gene expression, and the modulation of cell morphology and function.

6. **Desensitization:** Prolonged exposure to UTP can lead to receptor desensitization, a process that limits the duration of the cellular response. Desensitization involves the phosphorylation of the receptor, which reduces its affinity for UTP and inhibits its ability to activate G proteins.

In summary, UTP-GPCR activity involves a series of events, starting with ligand binding and culminating in the activation of downstream signaling pathways. These signaling pathways ultimately lead to a diverse array of cellular responses, highlighting the importance of UTP-GPCRs in cellular regulation and physiological processes.'
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Proteins (3)

Compounds (31)