galanin-activated signaling pathway

Definition

Target type: biologicalprocess

The series of molecular signals generated as a consequence of the peptide neurotransmitter galanin binding to a cell surface receptor. [GOC:lb, PMID:25691535]

Galanin, a neuropeptide widely distributed in the central and peripheral nervous system, exerts its biological effects through the activation of three G protein-coupled receptors: GalR1, GalR2, and GalR3. Upon binding of galanin to its receptors, a cascade of intracellular signaling events is initiated, leading to diverse physiological responses.

The galanin-activated signaling pathway begins with the activation of G protein-coupled receptors. GalR1 and GalR2 are coupled to Gi/o proteins, while GalR3 is coupled to Gq proteins. Activation of Gi/o proteins leads to the inhibition of adenylyl cyclase, resulting in a decrease in intracellular cAMP levels. This reduction in cAMP can modulate various downstream signaling pathways, including the protein kinase A (PKA) pathway.

In contrast, activation of GalR3 through Gq proteins stimulates phospholipase C (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol trisphosphate (IP3). DAG activates protein kinase C (PKC), while IP3 triggers the release of calcium from intracellular stores. The activation of PKC and the increase in intracellular calcium can regulate a variety of cellular processes, including gene expression, cell growth, and synaptic plasticity.

Beyond the classical signaling pathways, galanin can also activate non-canonical pathways involving the mitogen-activated protein kinase (MAPK) pathway, the Rho/Rac pathway, and the PI3K/Akt pathway. The activation of these pathways is receptor- and cell-type specific and contributes to the pleiotropic effects of galanin.

The galanin signaling pathway plays a crucial role in various physiological functions, including the regulation of feeding behavior, stress responses, pain perception, sleep-wake cycles, and memory formation. Dysregulation of galanin signaling has been implicated in several neurological and psychiatric disorders, such as anxiety, depression, epilepsy, Alzheimer's disease, and Parkinson's disease.

Therefore, understanding the intricacies of the galanin-activated signaling pathway is crucial for developing novel therapeutic strategies targeting these conditions.'
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Proteins (2)

Compounds (13)