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Pathway Description
Relaxin IV Signaling Pathway
Homo sapiens
Signaling Pathway
Created: 2025-07-07
Last Updated: 2025-10-02
The RXFP4 signaling pathway is initiated when the insulin-like peptide INSL5 binds to the RXFP4 receptor, a G protein-coupled receptor (GPCR) predominantly expressed in the human colon and hypothalamus. Upon ligand binding, RXFP4 primarily couples to Gi/o proteins, leading to inhibition of adenylyl cyclase and a subsequent decrease in intracellular cAMP levels. This downregulation of cAMP reduces protein kinase A (PKA) activity and alters downstream transcription factors such as CREB, ultimately affecting gene expression. Additionally, RXFP4 activation may trigger secondary signaling cascades through Gβγ subunits, influencing ion channel activity and MAPK/ERK pathways. In enteric neurons and L-cells of the colon, RXFP4 signaling modulates gut motility and hormone secretion, while in the hypothalamus, it plays a role in suppressing appetite and regulating energy balance. After activation, RXFP4 can be internalized via β-arrestin-mediated endocytosis, allowing for receptor recycling or further intracellular signaling. Overall, RXFP4 acts as a key component in gut-brain axis communication, integrating metabolic and neuroendocrine signals.
References
Relaxin IV Signaling Pathway References
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