THE PHOSPHORYLATION STATE OF THE FIGQY TYROSINE OF NEUROFASCIN DETERMINES ANKYRIN-BINDING ACTIVITY AND PATTERNS OF CELL SEGREGATION

Cell-cell recognition and patterning of cell contacts have a critical role in mediating reversible assembly of a variety of transcellular co mplexes in the nervous system. This study provides evidence for regula tion of cell interactions through modulation of ankyrin binding to neu rofascin, a member of the L1CAM family of nervous system cell adhesion molecules. The phosphorylation state of the conserved FIGQY tyrosine in the cytoplasmic domain of neurofascin regulates ankyrin binding and governs neurofascin-dependent cell aggregation as well as cell sortin g when neurofascin is expressed in neuroblastoma cells. These findings suggest a general mechanism for the patterning of cell contact based on external signals that regulate tyrosine phosphorylation of L1CAM me mbers and modulate their binding to ankyrin.