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  • The EMBO Journal (2007) 26, 4313 - 4323
  • doi:10.1038/sj.emboj.7601858

Published online: 13 September 2007

Regulation of nicotinic receptor trafficking by the transmembrane Golgi protein UNC-50

Stefan Eimer1,2,ab, Alexander Gottschalk3,ac, Michael Hengartner4,5,d, H Robert Horvitz4,5, Janet Richmond6, William R Schafer3, and Jean-Louis Bessereau1,2

  1. Ecole Normale Supérieure, Biology Department, Paris, France
  2. INSERM, U789, Biologie cellulaire de la synapse, Paris, France
  3. Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
  4. Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
  5. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
  6. Department of Biology, University of Illinois, Chicago, IL, USA

Correspondence to:

Jean-Louis Bessereau, Ecole Normale Supérieure, INSERM, U789, Biologie cellulaire de la synapse, 46 Rue d'Ulm, Paris 75005, France. Tel.: +33 1 44 32 23 05; Fax: +33 1 44 32 36 54; E-mail: jlbesse@biologie.ens.fr

aThese authors contributed equally to this work

bPresent address: European Neuroscience Institute (ENI), Center for Molecular Physiology of the Brain (CMPB), Goettingen 37077, Germany

cPresent address: Institute for Biochemistry, Goethe-University, Frankfurt 60438, Germany

dPresent address: Institute of Molecular Biology, University of Zurich, Zurich 8057, Switzerland

ePresent address: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK

Received 7 May 2007; Accepted 22 August 2007

Nicotinic acetylcholine receptors (AChRs) are pentameric ligand-gated ion channels that mediate fast synaptic transmission at the neuromuscular junction (NMJ). After assembly in the endoplasmic reticulum (ER), AChRs must be transported to the plasma membrane through the secretory apparatus. Little is known about specific molecules that mediate this transport. Here we identify a gene that is required for subtype-specific trafficking of assembled nicotinic AChRs in Caenorhabditis elegans. unc-50 encodes an evolutionarily conserved integral membrane protein that localizes to the Golgi apparatus. In the absence of UNC-50, a subset of AChRs present in body-wall muscle are sorted to the lysosomal system and degraded. However, the trafficking of a second AChR type and of GABA ionotropic receptors expressed in the same muscle cells is not affected in unc-50 mutants. These results suggest that, in addition to ER quality control, assembled AChRs are sorted within the Golgi system by a mechanism that controls the amount of cell-surface AChRs in a subtype-specific way.

  • Keywords:

    • C. elegans,
    • intracellular trafficking,
    • levamisole,
    • nicotinic acetylcholine receptor