Agrin induces the aggregation of postsynaptic proteins at the neuromuscular junction (NMJ). This activity requires the receptor-tyrosine kinase MuSK. Agrin isoforms differ in short amino acid stretches, which may influence their ability to induce NMJ formation. The study of agrin isoforms and their effects on NMJ formation is crucial for understanding the mechanisms of neuromuscular transmission and the development of novel therapeutic strategies for neuromuscular disorders.