Transmembrane protein that regulates gamma-aminobutyric acid type A receptor (GABA(A)R) trafficking, channel deactivation kinetics and pharmacology, necessary for fast inhibitory transmission in the brain (PubMed:31601770). Enhances the action of benzodiazepine, a primary GABA(A)Rs target drug, in the brain (PubMed:31601770). May affect channel kinetics of AMPA-type glutamate receptors (AMPAR), the brain's main excitatory neurotransmitter, necessary for synaptic hippocampal plasticity, and memory recall (Probable). May regulate the induction and maintenance of long-term potentiation at Schaffer collaterals/CA3-CA1 excitatory synapses (Probable). Interacts with GABA(A)R (GABA type A receptor) subunits GABRA1, GABRA2 and GABRG2; the interaction is direct (PubMed:31601770). Does not interact with GABRB2 and GABRB3 subunits (PubMed:31601770). Interacts with AMPAR subunits GRIA1, GRIA2 and GRIA3 and AMPAR auxiliary proteins SHISA6 and SHISA7 in heterologous cells (PubMed:26623514, PubMed:29199957). Interacts (via PDZ-binding motif) with DLG4/PSD-95 (via PDZ domain)in heterologous cells; the interaction is direct (PubMed:29199957). Localizes at GABAergic inhibitory synapses and colocalizes with gephyrin in hippocampal neurons. Mainly expressed in neurons (PubMed:26623514, PubMed:29199957, PubMed:31601770). Highly expressed in brain structures including cortex, striatum, olfactory bulb, amygdala hippocampus CA1-3 and dentate gyrus (at protein level) (PubMed:26623514, PubMed:29199957, PubMed:31601770). Expressed in the cerebral cortex on 17 dpc and in olfactory bulb and hippocampus on postnatal day 1 (P1) (PubMed:26623514). Expression in hippocampus increases during postnatal development and reaches a plateau after 3 weeks (PubMed:29199957). Expression is high during prenatal development and decreases in the thalamus and brainstem during postnatal development (PubMed:26623514). The GRID (GABA(A)R-interacting domain) is critical for its subcellular localization and interaction with GABA(A)R. The PDZ-binding motif interacts with PDZ-domain of scaffolding protein DLG4 in heterologous cells. N-glycosylated. Knockout mice show a decrease in miniature inhibitory postsynaptic currents frequency, but not amplitude, in CA1 pyramidal neurons (PubMed:31601770). Mice show impaired acquisition of contextual fear memory without affecting auditory fear learning or anxiety (PubMed:29199957). Decreased long-term potentiation of hippocampal glutamatergic synapses (PubMed:29199957). Belongs to the shisa family. SHISA7 has been reported to interact with AMPAR subunit GRIA1 in heterologous conditions and in the brain (PubMed:26623514, PubMed:29199957). However, it was later demonstrated that SHISA7 does not colocalize neither interact with AMPAR, but with GABA(A)R (PubMed:31601770). Therefore additional experiments are needed to understand the discrepancy for SHISA7 function. Truncated N-terminus.