IDENTIFICATION OF A TORPEDO HOMOLOG OF SAM68 THAT INTERACTS WITH THE SYNAPSE ORGANIZING PROTEIN RAPSYN

Nicotinic acetylcholine receptors (nAChRs) are initially expressed dif fusely on the surface of myotubes and, in response to neuronally deriv ed factors, cluster at the endplate to a final concentration of approx imately 10 000/mu m(2). The synaptic peripheral membrane protein rapsy n has been shown to mediate clustering of nAChRs in several systems, H ere we describe the use of the yeast two-hybrid system to identify pro teins that can interact with rapsyn. One of the clones we have identif ied is a Torpedo californica homolog of the Src-associated in mitosis protein (Sam68), We further show that Sam68, like rapsyn, is localized at the neuromuscular junction, (C) 1998 Federation of European Bioche mical Societies.