melanin-concentrating hormone receptor activity

Definition

Target type: molecularfunction

Combining with the cyclic peptide hormone melanin-concentrating hormone to initiate a change in cell activity. [GOC:mah]

Melanin-concentrating hormone receptor (MCHR) activity is a molecular function associated with the G protein-coupled receptor (GPCR) MCHR1 and MCHR2, which are involved in regulating a variety of physiological processes, including appetite, energy homeostasis, sleep-wake cycles, and stress response.

MCHR1 and MCHR2 are activated by the neuropeptide melanin-concentrating hormone (MCH), which is produced by neurons in the hypothalamus. Upon MCH binding, MCHRs undergo conformational changes that lead to the activation of downstream signaling pathways.

**MCHR1 Signaling:**
- MCHR1 couples primarily to the Gαs protein, which stimulates adenylate cyclase, leading to increased cAMP production. This, in turn, activates protein kinase A (PKA), which phosphorylates and activates downstream signaling molecules.
- MCHR1 also couples to Gαq proteins, triggering the phospholipase C (PLC) pathway. This pathway results in the production of diacylglycerol (DAG) and inositol trisphosphate (IP3). DAG activates protein kinase C (PKC), while IP3 releases intracellular calcium stores.

**MCHR2 Signaling:**
- MCHR2 predominantly couples to Gαi proteins, which inhibit adenylate cyclase, leading to decreased cAMP production. This inhibits PKA activity.
- MCHR2 can also couple to Gαq proteins, albeit to a lesser extent than MCHR1, activating the PLC pathway.

**Downstream Effects:**
- **Appetite and Energy Homeostasis:** MCHR1 activation in the hypothalamus promotes food intake and reduces energy expenditure, leading to weight gain. MCHR2 activation, on the other hand, may have a role in suppressing appetite.
- **Sleep-Wake Cycles:** MCHR1 activation promotes sleep and reduces wakefulness, while MCHR2 activation may have a role in promoting wakefulness.
- **Stress Response:** MCHR1 activation has been implicated in stress-induced anxiety and depression.
- **Other Physiological Processes:** MCHR1 and MCHR2 are also involved in regulating other physiological processes, including thermoregulation, cardiovascular function, and reproductive behavior.

The precise molecular mechanisms underlying these diverse physiological effects of MCHRs remain under investigation. However, it is clear that MCHR activity plays a crucial role in regulating a wide range of physiological functions, making it a potential target for the development of new therapeutic drugs for the treatment of various diseases, including obesity, insomnia, and anxiety disorders.'
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Proteins (1)

Compounds (7)