The overall aim of the proposed research is to gain an understanding of the molecular basis of neuronal differentiation. Nerve growth factor (NGF) induced differentiation of a clonal cell line, PC12, will be used as a model system for neuronal differentiation. The approaches involve the asessment of NGF mediated specific protein phosphorylations as a means of eliciting effects in the target cell which are involved in the expression of the neuronal phenotype. These approaches include (A) the identification of the kinase system responsible for NGF mediated protein phosphorylation. The protein substrate specificity and site of phosphorylation within a protein by NGF-activated kinase will be determined and the kinase identified with respect to known cellular protein kinases. This will be done by the use of specific activators and inhibitors of known kinases in vivo and by the direct measurement of specific kinase activities in cell homogenates. (B) Characteristics of the mechanism of NGF receptor transduction of the response will be determined with respect to functional characterization of the two-receptor types, subcellular localization, the means of adenylate cyclase activation and phosphatidylinositol turnover. (C) The analysis of tyrosin hydroxylase phosphorylation and activation with respect to the relationship of phosphorylation site and kinetic parameters of enzyme activation, subcellular localization of the different phpsphorylated forms, and the role of this modification in synaptogenesis in vivo in rat. (D) The general and specific requirements for NGF induced protein phosphorylation in neuronal differentiation will be investigated by specifically activating and blocking cellular kinases to cause or block respectively NGF effects on differentiation. These studies are intended to provide a basis for the eventual understanding of the role of protein kinase systems in the growth and development of neurons, the establishment of different developmental pathways of neurons, and the regulation of axonal guidance.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
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Neurology C Study Section (NEUC)
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State University New York Stony Brook
Schools of Arts and Sciences
Stony Brook
United States
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Philippidou, Polyxeni; Valdez, Gregorio; Akmentin, Wendy et al. (2011) Trk retrograde signaling requires persistent, Pincher-directed endosomes. Proc Natl Acad Sci U S A 108:852-7
Harrington, Anthony W; St Hillaire, Coryse; Zweifel, Larry S et al. (2011) Recruitment of actin modifiers to TrkA endosomes governs retrograde NGF signaling and survival. Cell 146:421-34
Joset, Armela; Dodd, Dana A; Halegoua, Simon et al. (2010) Pincher-generated Nogo-A endosomes mediate growth cone collapse and retrograde signaling. J Cell Biol 188:271-85
Bonanomi, Dario; Fornasiero, Eugenio F; Valdez, Gregorio et al. (2008) Identification of a developmentally regulated pathway of membrane retrieval in neuronal growth cones. J Cell Sci 121:3757-69
Valdez, Gregorio; Philippidou, Polyxeni; Rosenbaum, Julie et al. (2007) Trk-signaling endosomes are generated by Rac-dependent macroendocytosis. Proc Natl Acad Sci U S A 104:12270-5
Boykevisch, Sean; Zhao, Chen; Sondermann, Holger et al. (2006) Regulation of ras signaling dynamics by Sos-mediated positive feedback. Curr Biol 16:2173-9
Valdez, Gregorio; Akmentin, Wendy; Philippidou, Polyxeni et al. (2005) Pincher-mediated macroendocytosis underlies retrograde signaling by neurotrophin receptors. J Neurosci 25:5236-47
Wang, Sheng; Liu, Yan; Adamson, Crista L et al. (2004) The mammalian exocyst, a complex required for exocytosis, inhibits tubulin polymerization. J Biol Chem 279:35958-66
Kuruvilla, Rejji; Zweifel, Larry S; Glebova, Natalia O et al. (2004) A neurotrophin signaling cascade coordinates sympathetic neuron development through differential control of TrkA trafficking and retrograde signaling. Cell 118:243-55
Shao, Yufang; Akmentin, Wendy; Toledo-Aral, Juan Jose et al. (2002) Pincher, a pinocytic chaperone for nerve growth factor/TrkA signaling endosomes. J Cell Biol 157:679-91

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