Present address: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6.
A cytoplasmic motif targets neuroligin-1 exclusively to dendrites of cultured hippocampal neurons
Article first published online: 1 NOV 2005
European Journal of Neuroscience
Volume 22, Issue 9, pages 2381–2386, November 2005
How to Cite
Rosales, C. R., Osborne, K. D., Zuccarino, G. V., Scheiffele, P. and Silverman, M. A. (2005), A cytoplasmic motif targets neuroligin-1 exclusively to dendrites of cultured hippocampal neurons. European Journal of Neuroscience, 22: 2381–2386. doi: 10.1111/j.1460-9568.2005.04400.x
- Issue published online: 1 NOV 2005
- Article first published online: 1 NOV 2005
- Received 9 February 2005, revised 28 July 2005, accepted 2 August 2005
- neuronal polarity;
- protein targeting;
- synapse formation
The formation of neuronal synapses is thought to depend on trans-synaptic interactions between cell adhesion molecules (CAMs) on the surface of axons and dendrites. Synapses are highly asymmetric structures. Pre- and post-synaptic domains might therefore be assembled around heterophilic CAMs which are polarized to axons vs. dendrites. We here investigated the targeting of neuroligin (NLG)-1, a heterophilic CAM, which promotes synapse formation through interaction with its receptor β-neurexin in axons. We demonstrate that NLG-1 is highly polarized to the dendritic plasma membrane. Dendritic targeting relies on a cytoplasmic amino acid motif. By expressing chimeras of NLG-1 and CD8, an unpolarized protein, we show that the cytoplasmic domain of NLG-1 is necessary and sufficient for dendritic targeting. Furthermore, by truncation analysis we isolated a 32-amino-acid targeting motif. When appended to CD8 this cytoplasmic sequence is sufficient to direct exclusively dendritic localization of the protein. Analysis of yellow fluorescent protein-tagged NLG-1 revealed that vesicular structures containing NLG-1 are excluded from the axon indicating that polarized distribution may be achieved by direct dendritic transport. We propose that the strict polarity of NLG-1 contributes to the directional assembly of synapses during development of the central nervous system.