Enables several functions, including identical protein binding activity; molybdopterin adenylyltransferase activity; and molybdopterin molybdotransferase activity. Involved in establishment of protein localization; neurotransmitter receptor localization to postsynaptic specialization membrane; and synapse assembly. Acts upstream of or within Mo-molybdopterin cofactor biosynthetic process. Located in cytoplasm; inhibitory synapse; and postsynaptic specialization. Is extrinsic component of cytoplasmic side of plasma membrane. Is active in glycinergic synapse and postsynaptic specialization, intracellular component. Human ortholog(s) of this gene implicated in inherited metabolic disorder and molybdenum cofactor deficiency type C. Orthologous to human GPHN (gephyrin). [provided by Alliance of Genome Resources, Apr 2022]