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Hum Mol Genet. 2009 Oct 15;18(20):3822-31. doi: 10.1093/hmg/ddp325. Epub 2009 Jul 19.

Pathogenic human L1-CAM mutations reduce the adhesion-dependent activation of EGFR.

Author information

1
Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, 48109-2200, USA.

Abstract

L1-cell adhesion molecule (L1-CAM) belongs to a functionally conserved group of neural cell adhesion molecules that are implicated in many aspects of nervous system development. In many neuronal cells the adhesive function of L1-type CAMs induces cellular signaling processes that involves the activation of neuronal tyrosine protein kinases and among other functions regulates axonal growth and guidance. Mutations in the human L1-CAM gene are responsible for a complex neurodevelopmental condition, generally referred to as L1 syndrome. Several pathogenic L1-CAM mutations have been identified in humans that cause L1 syndrome in affected individuals without affecting the level of L1-CAM-mediated homophilic cell adhesion when tested in vitro. In this study, an analysis of two different pathogenic human L1-CAM molecules indicates that although both induce normal L1-CAM-mediated cell aggregation, they are defective in stimulating human epidermal growth factor receptor tyrosine kinase activity in vitro and are unable to rescue L1 loss-of-function conditions in a Drosophila transgenic model in vivo. These results indicate that the L1 syndrome-associated phenotype might involve the disruption of L1-CAM's functions at different levels. Either by reducing or abolishing L1-CAM protein expression, by interfering with L1-CAM's cell surface expression, by reducing L1-CAM's adhesive ability or by impeding further downstream adhesion-dependent signaling processes.

PMID:
19617634
PMCID:
PMC2748892
DOI:
10.1093/hmg/ddp325
[Indexed for MEDLINE]
Free PMC Article

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