Involved in the regulation of synaptic function at neuromuscular junctions (PubMed:19290026). Together with the liprin-alpha protein syd-2, may play a role in regulating the structure of the neuronal region, called the active zone, from which synaptic vesicles send neurotransmitter signals across the synapse (PubMed:19290026). Does not seem to be required for neuronal development (PubMed:19290026). May regulate the disassembly of focal adhesions (By similarity). Does not bind receptor-like tyrosine phosphatases type 2A (By similarity). Expressed in pharyngeal muscle, particularly posterior bulb, adjacent to the dorsal and ventral cord (but not in ventral cord neurons), and in body wall muscles. Defective locomotion, reduced pumping rate and reduced brood size (PubMed:19290026). Defects in presynaptic and postsynaptic structures and functions in muscle cells (PubMed:19290026). Resistant to the acetylcholinesterase inhibitor aldicarb and to levamisole, an agonist for postsynaptic acetylcholine receptors in muscles (PubMed:19290026). Double knockout with the syd-2 mutant ju37 increases resistance to aldicarb and levamisole (PubMed:19290026). Belongs to the liprin family. Liprin-beta subfamily.