Enables kinase binding activity. Involved in synaptic membrane adhesion. Acts upstream of or within homophilic cell adhesion via plasma membrane adhesion molecules and positive regulation of inhibitory postsynaptic potential. Located in several cellular components, including GABA-ergic synapse; inhibitory synapse; and neuronal cell body. Is expressed in hippocampus CA1. Orthologous to human IGSF9B (immunoglobulin superfamily member 9B). [provided by Alliance of Genome Resources, Apr 2022]