Neurofilaments (NF) are characteristic structures in neurons, but they become abnormally prominent and distributed in certain neurological disorders and toxin-induced neuropathies. Their precise role in normal neurons is unknown. NF are the only component of the neuronal cytoskeleton whose major components 1) are different proteins from those constituting the analogous structure in other kinds of cells and 2) are not all present in neuronal precursor cells, but whose synthesis is first initiated at the time that postmitotic neurons are generated. This suggests a specific role of NF in neuronal structure. The purpose of the proposed research is to examine aspects of the synthesis of NF proteins in relation to the growth of embryonic neurites and the integrity of mature neurons. Biochemical and cytological approaches will be used to examine the regulation of NF synthesis, posttranslational modification and intracellular distribution, during differentiation in vivo and in vitro as well as in mature neurons maintained in culture. The effects of certain exogenous hormones and growth factors, of agents interfering with cytoskeletal organization, and of neurotoxins, on the synthesis and processing of NF proteins will also be examined. Synthesis of NF proteins will be followed by incorporation of labeled amino acids. This will be compared with the synthesis of other neuronal cytoskeletal proteins, tubulin and actin, and of another neuron-specific (but not structural) protein, neuron-specific enolase. The types of posttranslational modifications to be examined include phosphorylation and proteolytic processing. The possibility of other types of modifications will be explored. Distribution of NF and other elements of the cytoskeleton will be examined by immunohistochemistry, using antibodies specific to individual NF proteins, as well as by electron microscopy. The results of these experiments will provide insight into the functional significance of NF in normal neurons and their relationship to altered neuronal properties in pathological conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024883-02
Application #
3409887
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1986-09-01
Project End
1988-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
2
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Florida
Department
Type
Schools of Arts and Sciences
DUNS #
073130411
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Fu, Z; Chakraborti, T; Morse, S et al. (2001) Four casein kinase I isoforms are differentially partitioned between nucleus and cytoplasm. Exp Cell Res 269:275-86
Fu, Z; Green, C L; Bennett, G S (1999) Relationship between casein kinase I isoforms and a neurofilament-associated kinase. J Neurochem 73:830-8
Green, C L; Bennett, G S (1998) Identification of four alternatively spliced isoforms of chicken casein kinase I alpha that are all expressed in diverse cell types. Gene 216:189-95
Shaw, G; Miller, R; Wang, D S et al. (1997) Characterization of additional casein kinase I sites in the C-terminal ""tail"" region of chicken and rat neurofilament-M. J Neurochem 69:1729-37
Bennett, G S; Quintana, R (1997) Identification of Ser-Pro and Thr-Pro phosphorylation sites in chicken neurofilament-M tail domain. J Neurochem 68:534-43
Hollander, B A; Bennett, G S; Shaw, G (1996) Localization of sites in the tail domain of the middle molecular mass neurofilament subunit phosphorylated by a neurofilament-associated kinase and by casein kinase I. J Neurochem 66:412-20
Bennett, G S; Basu, U; Hollander, B A et al. (1994) Differential sensitivity to inhibitors discriminates between two types of kinases responsible for in vivo phosphorylation of different sites in the carboxy-terminal tail of chicken neurofilament-M. Mol Cell Neurosci 5:358-68
Hollander, B A; Ayyub, C; Shaw, G et al. (1993) A neurofilament-associated kinase phosphorylates only a subset of sites in the tail of chicken midsize neurofilament protein. J Neurochem 61:2115-23
Hollander, B A; Bennett, G S (1992) Characterization of a neurofilament-associated kinase that phosphorylates the middle molecular mass component of chicken neurofilaments. Brain Res 599:237-45
Hollander, B A; Bennett, G S (1991) Lithium chloride alters cytoskeletal organization in growing, but not mature, cultured chick sensory neurons. J Neurosci Res 28:332-42

Showing the most recent 10 out of 13 publications