The overall aim of the proposed research is to achieve an understanding of the molecular basis of neuronal growth factor actions. These actions include the establishment, maintenance and regeneration of neuronal properties including morphology (axons and dendrites), the action potential mechanism, neurotransmitter storage and release, and synaptogenesis. One such growth factor, the Nerve Growth Factor (NGF), is the one best established to have such roles in vivo. NGF is required for the survival and differentiation of the major sympathetic and sensory peripheral neurons. Including those affected in familial dysautonomia, as well as of central nervous system neurons including those cholinergic neurons affected in Alzheimer's disease. Based on previous results with the neuron-like cell line, PC12, we have established a model for the signal transduction of NGF and the second messengers which generate the growth factor actions. In the model, the cellular photo-oncogenes src and ras, transduce the NGF signal into the stimulation of two second messenger systems, cAMP and phosphatidylinositol turnover, and of their associated protein kinases. The present research will test the model directly by specific inhibition of the second messengers and of the protein kinases followed by an assessment of the resulting inhibition of their predicted functional roles in NGF actions. One set of assays involves the analysis of tyrosine hydroxylase phosphorylation (by phosphopeptide mapping) and activation (by an in situ assay), an event which results in the enhancement of catecholamine neurotransmitter biosynthesis. Another assay involves analysis of transcriptional activation of another photo-oncogene, fos, believed to provide one link, through changes in gene expression, between short and long term NGF actions. The generation and growth of neural processes, caused by NGF, will be addressed in order to examine the role of the various second messengers in this important event. The specific roles of ras and src in NGF signal transduction will also be determined through their specific inhibition and by the introduction (by gene transfection) of their oncogenic """"""""activated"""""""" forms into cells, followed by assessment of NGF actions as described above. These approaches are expected to provide insights into the possible causes of the loss of critical neural properties as well as rational approaches to treatment in Parkinson's, Alzheimer's, familial dysautonomic and other related central and peripheral degenerating diseases.
| 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 |
| 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 |
| 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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