The gamma 2 subunit of GABA(A) receptors is required for maintenance of receptors at mature synapses.
The gamma2 subunit of GABA(A) receptor chloride channels is required for normal channel function and for postsynaptic clustering of these receptors during synaptogenesis. In addition, GABA(A) receptor function is thought to contribute to normal postnatal maturation of neurons. Loss of postsynaptic GABA(A) receptors in gamma2-deficient neurons might therefore reflect a deficit in maturation of neurons due to the reduced channel function. Here, we have used the Cre-loxP strategy to examine the clustering function of the gamma2 subunit at mature synapses. Deletion of the gamma2 subunit in the third postnatal week resulted in loss of benzodiazepine-binding sites and parallel loss of punctate immunoreactivity for postsynaptic GABA(A) receptors and gephyrin. Thus, the gamma2 subunit contributes to postsynaptic localization of GABA(A) receptors and gephyrin by a mechanism that is operant in mature neurons and not limited to immature neurons, most likely through interaction with proteins involved in trafficking of synaptic GABA(A) receptors.
Schweizer
Claude
C
Department of Biology, Penn State University, University Park, PA, USA.
Balsiger
Sylvia
S
Bluethmann
Horst
H
Mansuy
Isabelle M
IM
Fritschy
Jean-Marc
JM
Mohler
Hanns
H
Lüscher
Bernhard
B
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011963:Receptors, GABA-A / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013569:Synapses / Q000235:genetics* / Q000378:metabolism*
D002352:Carrier Proteins; C546280:Gabrg2 protein, mouse; D008565:Membrane Proteins; D011963:Receptors, GABA-A; C073441:gephyrin