Nerve Growth Factor (NGF) is a polypeptide growth factor that plays a critical role in the differentiation of immature neuroblasts and the subsequent survival of a subpopulation of mature neurons in both the peripheral and central nervous systems. NGF initiates its effects by binding to TrkA, a receptor type tyrosine kinase that when activated, initiates a signal transduction cascade resulting in Ras activation and the induction of early response genes. NGF-induced neurite outgrowth is also accompanied by extensive re-organization of the neuronal cytoskeleton to initiate neurite extension of neurite processes. Indeed, while the shape of filopodia and lamella in growth cones is largely determined by the organization of the actin cytoskeleton, little is known about how NGF and TrkA signaling is linked to the cytoskeleton. Over the past few years, we have been studying the Crk adaptor protein and its role during NGF-induced neuronal differentiation. Upon NGF addition to PC12 cells or primary dorsal root ganglia neurons, c-Crk is rapidly tyrosine phosphorylated at tyrosine 222. Interestingly, overexpression of mutant c-Crk carrying a mutation at Y222 (c-CrkY222F) impairs NGF-mediated neurite outgrowth in PC12 cells and abolishes TrkA- induced tyrosine phosphorylation of the cytoskeletal protein Paxillin. Our results indicate that Crk is involved in a novel aspect of TrkA signaling to adhesion complexes, thereby regulating actin re- organization and cell adhesion. In the present application, we shall study the molecular mechanisms by which c-Crk couples the TrkA receptor to the cytoskeleton, with the long-term goal to understand how NGF promotes differentiation and survival. Specifically, we plan to: (i) determine whether c-CrkY222F is a dominant negative c-Crk protein by impairing NGF-induced cell adhesion, (ii) determine the circuitry involved in NGF-induced tyrosine phosphorylation of c-Crk, (iii) determine the relationship between NGF- and adhesion-induced tyrosine phosphorylation of the c-Crk effector protein Paxillin, (iv) determine the biological role of Paxillin during NGF-mediated responses, and (v) determine the role of c-Crk during neuronal development using transgene approaches.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM055760-05
Application #
6490115
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Program Officer
Tompkins, Laurie
Project Start
1999-01-01
Project End
2003-12-31
Budget Start
2002-01-01
Budget End
2002-12-31
Support Year
5
Fiscal Year
2002
Total Cost
$268,423
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Biochemistry
Type
Schools of Medicine
DUNS #
605799469
City
Newark
State
NJ
Country
United States
Zip Code
07107
Sriram, G; Reichman, C; Tunceroglu, A et al. (2011) Phosphorylation of Crk on tyrosine 251 in the RT loop of the SH3C domain promotes Abl kinase transactivation. Oncogene 30:4645-55
Tunceroglu, Ahmet; Matsuda, Michiyuki; Birge, Raymond B (2010) Real-time fluorescent resonance energy transfer analysis to monitor drug resistance in chronic myelogenous leukemia. Mol Cancer Ther 9:3065-73
Sarkar, Paramita; Reichman, Charles; Saleh, Tamjeed et al. (2007) Proline cis-trans isomerization controls autoinhibition of a signaling protein. Mol Cell 25:413-26
Singh, Sukhwinder; D'mello, Veera; van Bergen en Henegouwen, Paul et al. (2007) A NPxY-independent beta5 integrin activation signal regulates phagocytosis of apoptotic cells. Biochem Biophys Res Commun 364:540-8
Kelic, S; Levy, S; Suarez, C et al. (2001) CD81 regulates neuron-induced astrocyte cell-cycle exit. Mol Cell Neurosci 17:551-60
Wu, R; Jurek, M; Sundarababu, S et al. (2001) The POU gene Brn-5 is induced by neuregulin and is restricted to myelinating Schwann cells. Mol Cell Neurosci 17:683-95
Strauch, B; Rodriguez, D M; Diaz, J et al. (2001) Autologous Schwann cells drive regeneration through a 6-cm autogenous venous nerve conduit. J Reconstr Microsurg 17:589-95; discussion 596-7