Signal-regulated proteins and fibroblast growth factor receptors: comparative immunolocalization in rat retina.

We compared the immunolocalization of fibroblast growth factor (FGF)-R1 and FGF-R2 with that of several intracellular signalling proteins in rat neural retina. Only the serine/threonine extracellular signal-related kinases (ERK) and lipocortin/annexin 6, a major calcium-binding protein, appeared to be co-localized with FGF-R1 and FGF-R2 in all subfields of the neural retina. In particular, ERK appeared to be present in perikarya of ganglion cells and synaptic layers as did these receptors. Possible implications of these results with regard to neuroprotective role of FGF are discussed.