EXTRACELLULAR SIGNAL-REGULATED KINASE (MAP KINASE) IMMUNOREACTIVITY IN THE RHESUS-MONKEY BRAIN

Extracellular signal regulated kinases (ERKs) are a recently cloned fa mily of genes that encode the MAP kinase protein kinases. They are hig hly expressed in brain and are believed to play an integral role in ne ural cellular responses to receptor activation. A role for ERKs has be en postulated in Alzheimer's disease, where they have been implicated in phosphorylation of tau in neurofibrillary tangles. We explored the neuroanatomic distribution of ERK immunoreactivity in the rhesus monke y brain. The hippocampal formation, especially the messy fiber zone an d the molecular layer of the dentate gyrus are the most heavily immuno stained areas. Cerebral cortex is, in general, more intensely stained in the supragranular layers. The caudate, putamen, and substantia nigr a contain more immunoreactivity than the claustrum, globus pallidus, o r thalamus with the exception of midline thalamic structures. These re sults suggest a marked regional and laminar distribution of ERKs in th e primate brain.