Enables acetylcholine receptor binding activity and acetylcholine receptor inhibitor activity. Acts upstream of or within several processes, including acetylcholine receptor signaling pathway; behavioral fear response; and negative regulation of protein localization to plasma membrane. Located in membrane. Is expressed in several structures, including alimentary system; limb; nervous system; sensory organ; and skin. Orthologous to human LYPD1 (LY6/PLAUR domain containing 1). [provided by Alliance of Genome Resources, Apr 2022]