Required to anchor acetylcholinesterase (ACHE) to the basal lamina of the neuromuscular junction and to the membrane of neuronal synapses in brain. Also able to organize ACHE into tetramers (By similarity). Interacts with ACHE, probably through disulfide bonds. In the brain, PRIMA linked to ACHE is found in membrane rafts. By RAF1. The proline-rich attachment domain (PRAD) binds the AChE catalytic subunits. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.