Neurofilaments (NF) are characteristic structures in normal neurons that become abnormally prominent and distributed in certain neuroicgical disorders and toxin-induced neuropathies. While clearly important in the development and maintenance of neuronal shape and intracellular organization their precise molecular function and the regulation thereof is not clear. The objectives of this project are to elucidate the key features of NF metabolism and how they are regulated in intact neurons. A further goal is to relate specific aspects of NF metabolism to events in the differentiation maturation and pathological alterations of the neuronal cytoskeleton. Biochemical and cytoiogical approaches will be used to examine the regulation of NF synthesis. Postransational modification and intracellular distribution during in vivo and in vitro differentiation as well as in mature neurons maintained in culture. Radioactive amino acid incorporation will be used to analyze the synthesis of NF proteins as compared with that of other neuronal cytoskeletal proteins tubulin and actin NF phosphorylation will be analyzed particularly the posttransiational phosphorylation of the avian middle Mr NF polypeptide, NF-M. This NF component is abundantly expressed in cultured neurons and is extensively phosphorylated over a prolonged time in culture and in vivo. It is proposed that the several sites become phosphorylated after translation in a specific sequence and that the different sites vary in the rate at which the subsequently exchange. This will be examined by establishing the kinetics of 32p uptake into the intact NF polypeptides as well as into individual proteolytic fragments. The effects of agents that perturb NF metabolism will be investigated, including Li+, which inhibits NF phosphorylation, tubulin metabolism and neurite growth. Analysis of this action of Li+, will assess in understanding basic aspects of reuroral cytoskeletal interactions as well as the clinically relevant mechanism of Li+, toxicity. Distribution of NF and other elements of the cytoskeleton will be examined by immunohistochemistry. Using antibodies specific to individual NF proteins at the light and EM level. The results of these experiments will provide insight into the functional significance of NF in normal neurons and in pathological conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024883-04
Application #
3409888
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1986-09-01
Project End
1993-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
4
Fiscal Year
1990
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