Glycine receptor

The glycine receptor ( GlyR ) is a protein complex in the cell membranes of animals Two side, which occurs mainly in nerve cells, but also in spermatozoa and macrophages. GlyR makes the membrane permeable to chloride ions, when a molecule binds to glycine GlyR. It is a controlled by glycine ion channel.

GlyR is composed of five protein subunits constructed ( 2α3β ) with four possible α - units are interchangeable. Mutations at GLRA1 and on GLRB gene are responsible for familial hyperekplexia ( STHE ).

GlyR heard as the GABAA receptor and the nicotinic acetylcholine receptor ( nAChR) to the class of ligand - gated ion channels ( ionotropic receptors ).

Function

GlyR is localized on the postsynaptic membrane of neurons and leads to its activation by glycine in a reduction of cell excitability. The excitation inhibition is induced by ligand binding in the influx of chloride ions into the cell. Depending on the concentration gradient of chloride ions between the extra - and intracellular space, the membrane potential changed to different degrees. It is negative in all cases. This means there is a hyperpolarization, which then inhibits the downstream cell ( inhibitory postsynaptic potential ).

Construction

As with the GABA ( A) R and nAChR consists of functional GlyR of five subunits ( pentamer ) which interlock to form a transmembrane protein with a central pore region together. There are two distinct in their amino acid sequence and size of the subunits (alpha, beta ) of the GlyR, each alpha-subunit has the binding site for the neurotransmitters, and the beta-subunit plays a structural role. Native assemble 2 alpha 3 beta subunits to the pentameric receptor. However, 5 alpha subunits alone can form a functional receptor. The alpha subunits can be further subdivided into four variants ( alpha1 to alpha4 ), whose occurrence depends on the region in the CNS and the development stage of the organism. In the organization of the GlyR at the postsynaptic binds to an intracellular location of this protein ( Gepherin ) which couples the receptor to the cytoskeleton.