Involved in maintenance of high-frequency synaptic transmission at hippocampal CA3-CA1 synapses. Regulates AMPA-type glutamate receptor (AMPAR) immobilization at postsynaptic density keeping the channels in an activated state in the presence of glutamate and preventing synaptic depression. May play a role in self-renewal and differentiation of spermatogonial stem cells by inhibiting canonical Wnt signaling pathway. . This is the function of ENSG00000188803 (SHISA6, shisa family member 6).