L1 syndrome mutations impair neuronal L1 function at different levels by divergent mechanisms

Item Type:	Article
Title:	L1 syndrome mutations impair neuronal L1 function at different levels by divergent mechanisms
Creators Name:	Schaefer, M.K.E. and Nam, Y.C. and Moumen, A. and Keglowich, L. and Bouche, E. and Kueffner, M. and Bock, H.H. and Rathjen, F.G. and Raoul, C. and Frotscher, M.
Abstract:	Mutations in the human L1CAM gene cause neurodevelopmental disorders collectively referred to as L1 syndrome. Here, we investigated cellular pathomechanisms underlying two L1 syndrome mutations, R184Q and W1036L. We demonstrate that these mutations cause partial endoplasmic reticulum (ER) retention of L1, reduce L1 cell surface expression, but do not induce ER stress in neuronal NSC-34 cells. We provide evidence that surface trafficking of mutated L1 is affected by defective sorting to ER exit sites and attenuated ER export. However, in differentiated neuronal cultures and long-term cultured hippocampal slices, the L1-R184Q protein is restricted to cell bodies, whereas L1-W1036L also aberrantly localizes to dendrites. These trafficking defects preclude axonal targeting of L1, thereby affecting L1-mediated axon growth and arborization. Our results indicate that L1 syndrome mutations impair neuronal L1 function at different levels, firstly by attenuating ER export and secondly by interfering with polarized neuronal trafficking.
Keywords:	L1CAM, Protein Trafficking, Cell Surface Expression, ER Export, ER Stress, Axon Growth, Axonal Targeting, Neural Development, Neurological Disorder, Hippocampus, Animals, Mice, Rats
Source:	Neurobiology of Disease
ISSN:	0969-9961
Publisher:	Elsevier
Volume:	40
Number:	1
Page Range:	222-237
Date:	October 2010
Official Publication:	https://doi.org/10.1016/j.nbd.2010.05.029
PubMed:	View item in PubMed

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