Regulator of G-protein signalling 9, also known as RGS9, is a human
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
,
which codes for a protein involved in regulation of
signal transduction
Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events, most commonly protein phosphorylation catalyzed by protein kinases, which ultimately results in a cellular ...
inside cells. Members of the
RGS family, such as RGS9, are signaling proteins that suppress the activity of
G protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ...
s by promoting their deactivation.
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There are two splice isoforms of RGS9 with quite different properties and patterns of expression. RGS9-1 is mainly found in the eye and is involved in regulation of phototransduction in
rod and cone cells of the
retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
, while RGS9-2 is found in the brain, and regulates dopamine and opioid signaling in the
basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
.
RGS9-2 is of particular interest as the most important RGS protein involved in terminating signalling by the
mu opioid receptor (although
RGS4 and
RGS17 are also involved), and is thought to be important in the development of tolerance to opioid drugs.
RGS9-deficient mice exhibit some motor and cognitive difficulties however, so inhibition of this protein is likely to cause similar side effects.
RGS9 is differentially regulated by Guanine nucleotide-binding protein subunit beta-5 (
GNB5) via the
DEP domain and DEP helical-extension domain in protein stability and membrane anchor association.
References
Further reading
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External links
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