The long-term goal of this research is an understanding of the events within the axon of a neuron that causes it to grow and to steer the correct course. Such an understanding is basic to an understanding of how the complex circuitry of the brain is correctly connected during development and of how some neurons regain appropriate functioning after injury. Thus the work is directly relevant to research on spinal cord injury, where paralysis results from the inability of central neurons to regenerate. It is also relevant to certain neuromuscular diseases, such as amyotrophic lateral sclerosis, whose course is markedly affected by new axon growth, in the form of collateral sprouting of the axons of motor neurons. Experiments are designed to examine events occurring in the tip of the growing axon, the growth cone, that underlie the sequence of morphological transformations in which membrane protrudes forward and matures into the axon cylinder. All of the experiments will use single giant neurons from the sea here, Aplysia californica, growing in culture. The size of these neurons will allow microinjection of large amounts of proteins. The core of the experimental approach will be the observation of living growth cones by video-enhanced differential interference contrast and flu orescence microscopy. Changes in the organization of the cytoskeleton will be monitored by the microinjection of fluorescent actin, tubulin, and actin-associated proteins into the cells. Sites of membrane addition will be identified by microinjection of fluorescent lipid and surface labeling with fluorescent lectin. Possible roles of protein phosphorylation will be probed by microapplication of protein kinase activators and inhibitors. Lastly, video microscopy will be combined with electron microscopy to probe the possible role of a large organelle (LIRB) unique to the growth cone.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS025161-02
Application #
3410324
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1987-07-01
Project End
1990-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
Schools of Medicine
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10027
Goldberg, D J; Foley, M S; Tang, D et al. (2000) Recruitment of the Arp2/3 complex and mena for the stimulation of actin polymerization in growth cones by nerve growth factor. J Neurosci Res 60:458-67
Tang, D; Goldberg, D J (2000) Bundling of microtubules in the growth cone induced by laminin. Mol Cell Neurosci 15:303-13
Grabham, P W; Foley, M; Umeojiako, A et al. (2000) Nerve growth factor stimulates coupling of beta1 integrin to distinct transport mechanisms in the filopodia of growth cones. J Cell Sci 113 ( Pt 17):3003-12
Grabham, P W; Goldberg, D J (1997) Nerve growth factor stimulates the accumulation of beta1 integrin at the tips of filopodia in the growth cones of sympathetic neurons. J Neurosci 17:5455-65
Goldberg, D J; Wu, D Y (1996) Tyrosine phosphorylation and protrusive structures of the growth cone. Perspect Dev Neurobiol 4:183-92
Wu, D Y; Wang, L C; Mason, C A et al. (1996) Association of beta 1 integrin with phosphotyrosine in growth cone filopodia. J Neurosci 16:1470-8
Goldberg, D J; Wu, D Y (1995) Inhibition of formation of filopodia after axotomy by inhibitors of protein tyrosine kinases. J Neurobiol 27:553-60
Goldberg, D J; Wu, D Y (1994) Regulation of events within the growth cone by extracellular cues: tyrosine phosphorylation. Prog Brain Res 103:75-83
Wu, D Y; Goldberg, D J (1993) Regulated tyrosine phosphorylation at the tips of growth cone filopodia. J Cell Biol 123:653-64
Goldberg, D J; Burmeister, D W (1992) Microtubule-based filopodium-like protrusions form after axotomy. J Neurosci 12:4800-7

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