PT  - JOURNAL ARTICLE
AU  - Sophie Marchand
AU  - Fabrizia Bignami
AU  - Françoise Stetzkowski-Marden
AU  - Jean Cartaud
TI  - The Myristoylated Protein Rapsyn is Cotargeted with the Nicotinic Acetylcholine Receptor to the Postsynaptic Membrane via the Exocytic Pathway
AID  - 10.1523/JNEUROSCI.20-02-00521.2000
DP  - 2000 Jan 15
TA  - The Journal of Neuroscience
PG  - 521--528
VI  - 20
IP  - 2
4099  - http://www.jneurosci.org/content/20/2/521.short
4100  - http://www.jneurosci.org/content/20/2/521.full
SO  - J. Neurosci.2000 Jan 15; 20
AB  - Rapsyn, a 43 kDa protein required to cluster nicotinic acetylcholine receptors (AChRs) at the neuromuscular junction, is tightly associated with the postsynaptic membrane via an N-terminal myristoylated site. Recent studies have shown that some acylated proteins associate with the exocytic pathway to become targeted to their correct destination. In this work, we usedTorpedo electrocyte to investigate the intracellular routing of rapsyn compared to those of AChR and Na,K-ATPase, the respective components of the innervated and noninnervated membranes. We previously demonstrated that these latter two proteins are sorted and targeted to plasma membrane via distinct populations of post-Golgi vesicles (Camus et al., 1998). Biochemical and immunoelectron microscopy analyses of various populations of post-Golgi vesicles immunopurified with magnetic beads led us to identify post-Golgi transport vesicles containing both rapsyn and AChR. These data suggest that rapsyn, as for AChR, specifically follows the exocytic pathway. Furthermore, immunogold-labeling experiments provided in situ evidence that AChR and rapsyn are cotransported in the same post-Golgi vesicles. Taken together, our observations suggest that rapsyn and AChR are cotargeted to the postsynaptic membrane.