Metabotropic glutamate receptor 6

Metabotropic glutamate receptor 6 (mGluR6 or GRM6) is a protein that in humans is encoded by the GRM6 gene. It is a type of G protein-coupled receptor (GPCR) that is activated by the neurotransmitter glutamate. mGluR6 is primarily found in the retina, where it plays a crucial role in the visual transduction pathway.

Structure

mGluR6 is a member of the metabotropic glutamate receptor family, which consists of eight different receptors (mGluR1 to mGluR8). These receptors are characterized by a seven-transmembrane domain structure and are divided into three groups (I, II, and III) based on their sequence similarity, pharmacological properties, and intracellular signaling mechanisms. mGluR6 belongs to group III.

Function

mGluR6 is predominantly expressed in the retina, specifically in the dendritic tips of ON-bipolar cells. Upon activation by glutamate, mGluR6 initiates a G protein-mediated intracellular signaling cascade that leads to the hyperpolarization of ON-bipolar cells. This process is essential for the conversion of light signals into electrical signals, a key step in visual perception.

Clinical significance

Mutations in the GRM6 gene have been associated with several forms of inherited retinal degenerative diseases, including autosomal recessive congenital stationary night blindness (CSNB). Patients with CSNB have difficulty seeing in low light conditions due to a defect in signal transmission from the photoreceptors to the bipolar cells in the retina.

Research

Research on mGluR6 has primarily focused on its role in the retina and its potential as a therapeutic target for retinal diseases. Studies have also investigated the receptor's structure, signaling mechanisms, and the effects of various agonists and antagonists.

See also

• Metabotropic glutamate receptor
• G protein-coupled receptor
• Glutamate receptor
• Congenital stationary night blindness

References

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