gephyrine

Gephyrine is a term that most commonly corresponds to gephyrin, a neuronal cytoplasmic scaffolding protein that clusters inhibitory receptors at synapses. The spelling "gephyrine" is less common and may be a variant or misspelling of gephyrin.

Gephyrin is encoded by the GPHN gene and is essential for the postsynaptic organization of inhibitory synapses. It forms a scaffold that anchors glycine receptors and GABA_A receptors at the postsynaptic membrane, enabling effective inhibitory neurotransmission. The protein interacts with glycine receptor beta subunits and α-subunits of GABA_A receptors, and it associates with collybistin (ARHGEF9), which helps target gephyrin to inhibitory synapses. Gephyrin has a modular architecture with N- and C-terminal domains that mediate self-assembly and receptor binding, connected by a central linker. Alternative splicing generates multiple isoforms with distinct localization and binding properties.

Localization and regulation: Gephyrin clusters are found at inhibitory synapses throughout the central nervous system and spinal cord. Its clustering is dynamically regulated by synaptic activity and signaling pathways; phosphorylation and proteolytic processing influence receptor recruitment and scaffold stability.

Clinical relevance: Disruption of gephyrin clustering or expression affects inhibitory synaptic transmission and has been investigated in the context of epilepsy, neurodevelopmental and psychiatric disorders. Mutations in ARHGEF9, which interacts with gephyrin, cause X-linked intellectual disability and epilepsy, illustrating the importance of this scaffolding system.

See also: GPHN, glycine receptor, GABA_A receptor, collybistin (ARHGEF9).