Cellular and Molecular Neurobiology

, Volume 27, Issue 1, pp 11–31

The Role of Cytoplasmic Serine Residues of the Cell Adhesion Molecule L1 in Neurite Outgrowth, Endocytosis, and Cell Migration


DOI: 10.1007/s10571-006-9113-1

Cite this article as:
Schultheis, M., Diestel, S. & Schmitz, B. Cell Mol Neurobiol (2007) 27: 11. doi:10.1007/s10571-006-9113-1


1. The cell adhesion molecule L1 has been implicated in adhesion and migration of cells, in axon growth, guidance, and fasciculation, in myelination and synaptic plasticity. The cytoplasmic domain of neuronal L1 is highly conserved between species and has been shown to be phosphorylated at serine and tyrosine residues.

2. To investigate the significance of L1 serine phosphorylation, mutants of L1 were generated in which ser-1152, ser-1181, ser-1204, and ser-1248 were exchanged for leucine and rat B35 neuroblastoma cells were stably transfected with the L1-cDNA constructs.

3. Neurite outgrowth on poly-l-lysine (PLL) as substrate was determined either with or without differentiation into a neuronal phenotype with dbcAMP. In addition, antibody-induced endocytosis and cell migration were examined.

4. Our observations indicate that phosphorylation of single serine residues of the cytoplasmic domain of L1 contributes to neurite outgrowth through different mechanisms. Neurite growth is increased when ser-1152 or ser-1181 is replaced by a non-phosphorylatable leucine and decreased when ser-1204 or ser-1248 is mutated to leucine. Furthermore, mutation of ser-1181 to leucine results in strongly enhanced antibody-induced endocytosis of L1 and also in enhanced cell migration.


cell adhesion molecule L1 serine to leucine mutations transfected B35 neuroblastoma cells neurite growth endocytosis cell migration 

Abbreviations used:


adaptor protein-2


ezrin, radixin, moesin family of membrane-cytoskeleton linking proteins


caseinkinase 2

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  1. 1.Department of Biochemistry, Institute of Animal SciencesUniversity of BonnBonnGermany