title: Spatial, temporal, and cellular distribution of the activated extracellular signal regulated kinases 1 and 2 in the developing and mature rat cerebellum.
abstract: The extracellular signal regulated kinases 1 and 2 (ERK1/2) are important members of an intracellular signaling cascade that is involved in many aspects of the cellular physiology and development of neurons and glia. ERK1/2 are expressed in many brain regions including the cerebellum; however, their role during cerebellar development is poorly understood. Immunohistochemical approaches using phosphorylation-state specific antiserum that recognizes only the activated-ERK1/2 (pERK) were used to characterize the spatial and temporal patterns of activated-ERK in the developing and adult rat cerebellum. The distribution and cell type-specificity of pERK-immunoreactivity (IR) followed an age-related pattern, with the density of pERK-IR Purkinje cells decreasing between P6 and P15 and increasing at later times. Immunopositive granule cell neurons increased from P6 to P12, became decreased during much of late postnatal cerebellar development, and absent in adults. Co-localization of pERK with glial fibrillary acidic protein or the neuronal marker beta-tubulin revealed that activated ERK is present in maturing Purkinje and granule cells, and the soma of Bergmann glia on P4, P10 and P15; pERK was detected in astrocytes on P10 and P15. Associated with weaning, there was a general increase in activated-ERK in all cell types on P22. In adults, pERK-IR was confined to the Purkinje cell layer and scattered cells in the corpus medullare. In summary, a high degree of developmental plasticity was observed in the spatiotemporal distribution of cerebellar pERK-IR suggesting that the ERK-pathway plays a dynamic role in regulating neuronal and glial migration, proliferation and differentiation in the developing cerebellum. In the mature cerebellum, ERK signaling may also mediate postsynaptic information processing.
authors.affiliation: Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, P.O. Box 670575 Cincinnati, OH 45267-0575, USA.
authors.forename: Attila
authors.initials: A
authors.lastname: Zsarnovszky
authors.forename: Scott M
authors.initials: SM
authors.lastname: Belcher
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002452:Cell Count / Q000379:methods; D002531:Cerebellum / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007211:Indoles / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D011689:Purkinje Cells / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005904:Glial Fibrillary Acidic Protein; D007211:Indoles; C007293:DAPI; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases