Dab1, a homolog of the Drosophila Disabled protein, is an adaptor protein
involved in neural development. This cytoplasmic protein is tyrosine-phosphorylated
during rapid expansion of the developing nervous system, and it
is thought to interact with other proteins via a domain similar to the PTB
domains of the Shc family. Dab1 has been shown to interact with the SH2
domains of Src, Fyn and Abl. Mutations in Dab1 result in widespread abnormalities
in the brain, similar to those seen in Reelin mutants. Reelin is a
secreted protein thought to play a role in directing migrating neurons.
Evidence suggests that Dab1 functions downstream of Reelin in a signaling
pathway involved in positioning cells in the developing brain. Dab2 (also
designated DOC-2) is a mitogen-responsive phosphoprotein that binds the
SH3 domain of Grb2, and it is thought to be a negative regulator of growth.