cAMP-induced differentiation of human neuronal progenitor cells is mediated by nuclear fibroblast growth factor receptor-1 (FGFR1).
Activation of cAMP signaling pathway and its transcriptional factor cyclic AMP response element binding protein (CREB) and coactivator are key determinants of neuronal differentiation and plasticity. We show that nuclear fibroblast growth factor receptor-1 (FGFR1) mediates cAMP-induced neuronal differentiation and regulates CREB and CREB binding protein (CBP) function in alpha-internexin-expressing human neuronal progenitor cells (HNPC). In proliferating HNPC, FGFR1 was associated with the cytoplasm and plasma membrane. Treatment with dB-cAMP induced nuclear accumulation of FGFR1 and caused neuronal differentiation, accompanied by outgrowth of neurites expressing MAP2 and neuron-specific neurofilament-L protein and enolase. HNPC transfected with nuclear/cytoplasmic FGFR1 or non-membrane FGFR1(SP-/NLS), engineered to accumulate exclusively in the cell nucleus, underwent neuronal differentiation in the absence of cAMP stimulation. In contrast, FGFR1/R4, with highly hydrophobic transmembrane domain of FGFR4, was membrane associated, did not enter the nucleus and failed to induce neuronal differentiation. Transfection of tyrosine kinase-deleted dominant negative receptor mutants, cytoplasmic/nuclear FGFR1(TK-) or nuclear FGFR1(SP-/NLS)(TK-), prevented cAMP-induced neurite outgrowth. Nuclear FGFR1 localized in speckle-like domains rich in phosphorylated histone 3 and splicing factors, regions known for active RNA transcription and processing, and activated the neurofilament-L gene promoter. FGFR1(SP-/NLS) transactivated CRE, up-regulated phosphorylation and transcriptional activity of CREB and stimulated the activity of CBP several-fold. Thus, cAMP-induced nuclear accumulation of FGFR1 provides a signal that triggers molecular events leading to neuronal differentiation.
Stachowiak
E K
EK
Molecular and Structural Neurobiology and Gene Therapy Program, Department Pathology and Anatomical Sciences, State University of New York, Buffalo 14214, USA.
Fang
X
X
Myers
J
J
Dunham
S
S
Stachowiak
M K
MK
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D050882:CREB-Binding Protein; D002454:Cell Differentiation / Q000187:drug effects*; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005799:Genes, Dominant; D006801:Humans; D016297:Mutagenesis, Site-Directed; D016501:Neurites / Q000187:drug effects; D016900:Neurofilament Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology*; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection
D017362:Cyclic AMP Response Element-Binding Protein; D016900:Neurofilament Proteins; D009687:Nuclear Proteins; D017468:Receptors, Fibroblast Growth Factor; D015534:Trans-Activators; C044882:neurofilament protein L; D016222:Fibroblast Growth Factor 2; D003994:Bucladesine; D000242:Cyclic AMP; D050882:CREB-Binding Protein; C494363:CREBBP protein, human; C496348:FGFR1 protein, human; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1