Journal of Neuroscience, Vol 12, 3956-3967, Copyright © 1992 by Society for Neuroscience
Cek5, a membrane receptor-type tyrosine kinase, is in neurons of the embryonic and postnatal avian brain
EB Pasquale, TJ Deerinck, SJ Singer and MH Ellisman
La Jolla Cancer Research Foundation, California 92037.
Cek5 is a recently identified receptor-type tyrosine kinase of the Eph
subclass that is nearly ubiquitously expressed during embryonic development
(Pasquale, 1991). Cek5 is predominantly expressed in the avian CNS
throughout development, and high levels remain apparent in adult neurons.
By means of immunofluorescence microscopy and high- resolution
immunoelectron microscopy, Cek5 was found to be expressed in many regions
of the chicken brain at various developmental stages, most notably in the
hippocampus and cerebellum. The highest concentration of Cek5 was observed
in the molecular layer of the cerebellum, associated within the axons of
mature granule cells (parallel fibers) and with the cell bodies of immature
granule cells. In the axons of parallel fibers, Cek5 was concentrated in
the fasciculated nonsynaptic portions. This localization, together with the
"adhesion" motifs present in the Cek5 extracellular region suggest that
Cek5 may interact with other cell surface-associated molecules and be
involved in the growth, guidance, and/or bundling of certain unmyelinated
axonal processes. Alternatively (or in addition), Cek5 may represent the
receptor for a neurotrophic substance, similar to several other neuronal
transmembrane tyrosine kinases.