title: Brain derived neurotrophic factor induces a rapid upregulation of synaptophysin and tau proteins via the neurotrophin receptor TrkB in rat cerebellar granule cells.
abstract: We have examined the effects of neurotrophins brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) on the expression of the maturation-specific proteins synaptophysin and tau, and the growth-associated protein (GAP)-43 in cerebellar granule cells. We find that BDNF but not NGF rapidly (within 2 h) upregulates levels of synaptophysin, tau and c-Fos correlating with expression of the neurotrophin receptor TrkB. The rapid increase in synaptophysin is not preceded by c-Fos elevation suggesting a post-transcriptional mechanism may be involved. In contrast, no upregulation of GAP-43 levels are seen within this time period. Phorbol ester mimics the effects of BDNF, indicating that protein kinase C (PKC) is either a component of, or feeds into the signalling mechanism. We conclude that BDNF, characterized to be survival promoting early in differentiation of cerebellar granule cells, enhances maturation at a later stage.
authors.affiliation: Department of Biochemistry and Pharmacy, Abo Akademi University, Biocity, Turku, Finland. ecoffey@aton.abo.fi
authors.forename: E T
authors.initials: ET
authors.lastname: Coffey
authors.forename: K E
authors.initials: KE
authors.lastname: Akerman
authors.forename: M J
authors.initials: MJ
authors.lastname: Courtney
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D002531:Cerebellum / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D015151:Immunoblotting; D016760:Proto-Oncogene Proteins c-fos / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D051381:Rats; D020801:Receptor, Ciliary Neurotrophic Factor; D017475:Receptors, Nerve Growth Factor / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D016708:Synaptophysin / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D016875:tau Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D019208:Brain-Derived Neurotrophic Factor; D016760:Proto-Oncogene Proteins c-fos; D020801:Receptor, Ciliary Neurotrophic Factor; D017475:Receptors, Nerve Growth Factor; D016708:Synaptophysin; D016875:tau Proteins