Consider Agrin signaling in the formation of neuromuscular junctions in vertebrates. Shp2 is a protein tyrosine phosphatase that counteracts the tyrosine kinase activity of MuSK. Rapsyn interacts with the acetylcholine receptors and induces their agrin-dependent clustering. Indicate whether each of the following is expected to enhance (E) or suppress (S) acetylcholine receptor clustering in this process. Your answer would be a four-letter string composed of letters E and S only, e.g. EEEE.
( ) Specific inhibition of Shp2
( ) Loss of Rapsyn
( ) Loss of LRP4
( ) Constitutive activation of MuSK