Gq Signaling Pathway
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General Pharm
- Gs / Gi Pathway
- Gq Signaling Pathway
- Alpha-1 (Adrenergic) Receptors
- Alpha-2 (Adrenergic) Receptors
- Beta-1 (Adrenergic) Receptors
- Beta-2 (Adrenergic) Receptors
- Beta-3 (Adrenergic) Receptors
- M1 (Muscarinic) Receptors
- M2 (Muscarinic) Receptors
- M3 (Muscarinic) Receptors
- D1 (Dopamine) Receptors
- D2 (Dopamine) Receptors
- H1 (Histamine) Receptors
- H2 (Histamine) Receptors
- V1 (Vasopressin) Receptors
- V2 (Vasopressin) Receptors
Summary
The Gq signaling pathway is a cell signaling pathway that starts with binding of a G-protein coupled receptor associated with a Gq protein subunit. This Gq protein subunit then stimulates the activation of PLC, or phospholipase C. PLC is an enzyme that breaks down a membrane phospholipid, PIP2, into two intermediates, diacylglycerol (DAG) and inositol triphosphate (IP3). DAG goes on to activate another enzyme, protein kinase C (PKC). The other intermediate produced, IP3, induces the release of calcium ions from the sarcoplasmic or endoplasmic reticulum. This influx of calcium causes smooth muscle contraction.
Key Points
- Gq Signaling Pathway
- Gq subunit → PLC (phospholipase C)
- Binding to a Gq-coupled receptor causes activation of a Gq protein subunit, which then acts as a second messenger to activate phospholipase C (PLC)
- PLC cleaves PIP2 → DAG (diacylglycerol) and IP3 (inositol triphosphate)
- PIP2 is a cell membrane phospholipid which is cleaved by phospholipase C to form two intermediates: diacylglycerol (DAG) and inositol triphosphate (IP3)
- DAG (diacylglycerol) → PKC (protein kinase C)
- Protein kinase C (PKC) is activated by DAG, as well as by calcium ions released from sarcoplasmic reticulum under the influence of IP3
- IP3 (inositol triphosphate) → opens calcium channels
- Released calcium further stimulates PKC, and also induces smooth muscle contraction
- Calcium influx → smooth muscle contraction
- Gq subunit → PLC (phospholipase C)