Sodium- and chloride-dependent glycine transporter 2, also known as glycine transporter 2 (GlyT2), is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''SLC6A5''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
The glycine transporter 2 is a membrane protein which recaptures
glycine
Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (G ...
, a major inhibitory transmitter in the
spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...
and
brainstem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...
. GlyT2 is a specific marker of glycinergic neurons and a member of the Na
+ and Cl
−-coupled transporter family SLC6. Glycine uptake mediated by GlyT2 is electrogenic, coupled to three Na
+ and one Cl
− (i.e. two positive charges per glycine). In humans, GlyT2 is encoded by the ''SLC6A5''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
. Inactivation of GlyT2 in
knockout
A knockout (abbreviated to KO or K.O.) is a fight-ending, winning criterion in several full-contact combat sports, such as boxing, kickboxing, Muay Thai, mixed martial arts, karate, some forms of taekwondo and other sports involving striking, ...
mice is lethal during the second post-natal week as the absence of GlyT2 disrupts inhibitory transmission by reducing glycine release. Mutations in SLC6A5 gene are responsible for a presynaptic form of
hyperekplexia
Hyperekplexia (; "exaggerated surprise") is a neurological disorder characterized by a pronounced startle response to tactile or acoustic stimuli and an ensuing period of hypertonia. The hypertonia may be predominantly truncal, attenuated durin ...
, a genetic disease causing increased
startle
In animals, including humans, the startle response is a largely unconscious defensive response to sudden or threatening stimuli, such as sudden noise or sharp movement, and is associated with negative affect.Rammirez-Moreno, David. "A computatio ...
reflex. GlyT2 main physiological role is to recapture glycine released in the synaptic cleft and to maintain high glycine concentration in the presynaptic neuron. Therefore, chronic inhibition of GlyT2 will deplete intracellular storage of glycine and limit its accumulation in synaptic vesicles.
Inhibitors
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Amoxapine
Amoxapine, sold under the brand name Asendin among others, is a tricyclic antidepressant (TCA). It is the N-demethylation, demethylated metabolite of loxapine. Amoxapine first received marketing approval in the United States in 1980, approximat ...
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Ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
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N-Arachidonylglycine (NAGly)
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Opiranserin (VVZ-149)
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ORG-25543
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VVZ-368
See also
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Sodium:neurotransmitter symporter
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Solute carrier family
The solute carrier (SLC) group of membrane transport proteins include over 400 members organized into 66 families. Most members of the SLC group are located in the cell membrane. The SLC gene nomenclature system was originally proposed by the HUGO ...
References
Further reading
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Solute carrier family
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