Neuronal Guanine Nucleotide Exchange Factor (NGEF)

Eph receptors transduce short-range repulsive signals for axon guidance by modulating actin dynamics within growth cones. The predicted 620-amino acid mouse ephexin protein contains a tandem Dbl homology-pleckstrin homology (DH-PH) motif and a C-terminal SH3 domain.

Mouse Ngef is 95% identical to the 527-amino acid partial human sequence. Northern blot analysis revealed expression of a 2.8-kb transcript in mouse and human brain, with predominant expression in caudate nucleus and lower expression in amygdala and hippocampus. Analysis of mouse embryos detected strong expression on day 7 and relatively little expression at later stages of gestation. Functional analysis suggested that mouse Ngef has transforming potential.