GABA receptor: Difference between revisions

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== Structure ==

There are two major classes of GABA receptors abundant throughout neuronal cell types, ionotropic and metabotropic (Cryan, 2005). Metabotropic GABAB receptors are a specific division of the GABA receptor that induce a change in membrane potential through the action of a second messenger pathway (Kerr, 1995). The GABAB receptor functions as a heterodimer of two subunits, GABAB1 and GABAB2 (Figure 1: GABAB1 - gray; GABAB2 - green). Heterodimerization is accomplished using interactions of the coiled-coil motifs within the C-termini and interactions between the transmembrane and extracellular domains (Cryan, 2005). Additionally, there are two GABAB1 isoforms that differ at the N-termini where there are two sushi domains (Cryan, 2005). These sushi domains on the GABAB1 subunit are key to the receptor's interaction with other proteins as well as axonal signaling (Cryan, 2005). The two GABAB subunits link together as GABAB2 connects to GABAB1 at the endoplasmic reticulum via their intracellular C-terminus to form the heterodimer GABAB receptor (Sigma Aldrich). The GABAB receptor exists in two different forms - in the resting state (Figure 1) and the active state (Figure 2)(Geng, 2013). Geng et. al. has found, using the GABAB crystal structures, that both subunits exist in open conformations while at rest. Upon binding with the agonist, the GABAB1 subunit closes(Geng, 2013) (see below). Additionally, it was found that the agonist is bound in the interdomain crevice of the GABAB1 subunit due to an overlap of amino acid residues (Geng, 2013). This conformation change is highlighted in Figures 1 and 2 as one may notice the reduction in the space between GABAB subunits upon binding with GABA.

There are two major classes of GABA receptors abundant throughout neuronal cell types, ionotropic and metabotropic (Cryan, 2005). Metabotropic GABAB receptors are a specific division of the GABA receptor that induce a change in membrane potential through the action of a second messenger pathway (Kerr, 1995). The GABAB receptor functions as a heterodimer of two subunits, GABAB1 and GABAB2 (Figure 1: GABAB1 - gray; GABAB2 - green). Heterodimerization is accomplished using interactions of the coiled-coil motifs within the C-termini and interactions between the transmembrane and extracellular domains (Cryan, 2005). Additionally, there are two GABAB1 isoforms that differ at the N-termini where there are two sushi domains (Cryan, 2005). These sushi domains on the GABAB1 subunit are key to the receptor's interaction with other proteins as well as axonal signaling (Cryan, 2005). The two GABAB subunits link together as GABAB2 connects to GABAB1 at the endoplasmic reticulum via their intracellular C-terminus to form the heterodimer GABAB receptor (Sigma Aldrich).

The GABAB receptor exists in two different forms - in the resting state (Figure 1) and the active state (Figure 2)(Geng, 2013). Geng et. al. has found, using the GABAB crystal structures, that both subunits exist in open conformations while at rest. Upon binding with the agonist, the GABAB1 subunit closes(Geng, 2013) (see below). Additionally, it was found that the agonist is bound in the interdomain crevice of the GABAB1 subunit due to an overlap of amino acid residues (Geng, 2013). This conformation change is highlighted in Figures 1 and 2 as one may notice the reduction in the space between GABAB subunits upon binding with GABA.

== Function ==

GABA receptor: Difference between revisions

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 == Structure ==
-There are two major classes of GABA receptors abundant throughout neuronal cell types, ionotropic and metabotropic (Cryan, 2005). Metabotropic GABAB receptors are a specific division of the GABA receptor that induce a change in membrane potential through the action of a second messenger pathway (Kerr, 1995). The GABAB receptor functions as a heterodimer of two subunits, GABAB1  and GABAB2 (Figure 1: GABAB1 - gray; GABAB2 - green). Heterodimerization is accomplished using interactions of the coiled-coil motifs within the C-termini and interactions between the transmembrane and extracellular domains (Cryan, 2005). Additionally, there are two GABAB1 isoforms that differ at the N-termini where there are two sushi domains (Cryan, 2005). These sushi domains on the GABAB1 subunit are key to the receptor's interaction with other proteins as well as axonal signaling (Cryan, 2005). The two GABAB subunits link together as GABAB2 connects to GABAB1 at the endoplasmic reticulum via their intracellular C-terminus to form the heterodimer GABAB receptor (Sigma Aldrich). The GABAB receptor exists in two different forms - in the resting state (Figure 1) and the active state (Figure 2)(Geng, 2013). Geng et. al. has found, using the GABAB crystal structures, that both subunits exist in open conformations while at rest. Upon binding with the agonist, the GABAB1 subunit closes(Geng, 2013) (see below). Additionally, it was found that the agonist is bound in the interdomain crevice of the GABAB1 subunit due to an overlap of amino acid residues (Geng, 2013). This conformation change is highlighted in Figures 1 and 2 as one may notice the reduction in the space between GABAB subunits upon binding with GABA.
+There are two major classes of GABA receptors abundant throughout neuronal cell types, ionotropic and metabotropic (Cryan, 2005). Metabotropic GABAB receptors are a specific division of the GABA receptor that induce a change in membrane potential through the action of a second messenger pathway (Kerr, 1995). The GABAB receptor functions as a heterodimer of two subunits, GABAB1  and GABAB2 (Figure 1: GABAB1 - gray; GABAB2 - green). Heterodimerization is accomplished using interactions of the coiled-coil motifs within the C-termini and interactions between the transmembrane and extracellular domains (Cryan, 2005). Additionally, there are two GABAB1 isoforms that differ at the N-termini where there are two sushi domains (Cryan, 2005). These sushi domains on the GABAB1 subunit are key to the receptor's interaction with other proteins as well as axonal signaling (Cryan, 2005). The two GABAB subunits link together as GABAB2 connects to GABAB1 at the endoplasmic reticulum via their intracellular C-terminus to form the heterodimer GABAB receptor (Sigma Aldrich).
+The GABAB receptor exists in two different forms - in the resting state (Figure 1) and the active state (Figure 2)(Geng, 2013). Geng et. al. has found, using the GABAB crystal structures, that both subunits exist in open conformations while at rest. Upon binding with the agonist, the GABAB1 subunit closes(Geng, 2013) (see below). Additionally, it was found that the agonist is bound in the interdomain crevice of the GABAB1 subunit due to an overlap of amino acid residues (Geng, 2013). This conformation change is highlighted in Figures 1 and 2 as one may notice the reduction in the space between GABAB subunits upon binding with GABA.
 == Function ==