The proposed work builds on previous studies establishing (1) that GTP cyclohydrolase I, the rate-limiting enzyme in the synthesis of the cofactor tetrahydrobiopterin, interacts directly with tyrosine hydroxylase in protein complexes and (2) that a transmembrane protein, Catecholamines-up (or Catsup), acts as a negative regulator of GTP cyclohydrolase and tyrosine hydroxylase, also forming complexes with these enzymes. Catsup is hypothesized to regulate catecholamine expression by sequestering these key enzymes until a signal is received, resulting in the release of the two enzymes and their activation by phosphorylation.
The specific aims of this proposal, which test aspects of this model, are: To determine whether the interaction of Catsup with TSH and GTPCH is direct. GST-fusion pull-down assays and yeast two-hybrid assays are proposed to address this question. To determine whether phosphorylation has a role in regulating the formation of complexes with Catsup using in vitro manipulation of the interacting proteins. To use yeast reverse two-hybrid interaction assays to map binding domains if interactions are direct, or to use yeast two-hybrid cDNA library screens to search for interacting proteins if interactions between Catsup and these two enzymes are indirect. To conduct mutant screens to isolate new mutations in genes that interact with Catsup. Regulation of catecholamine expression is a key feature in normal neural function, and defects in this pathway are associated with a variety of neurological disorders including Parkinson's disease and hereditary progressive dystonia. The very high degree of sequence conservation between these key genes in catecholamine expression in Drosophila and their counterparts in mammals, suggest that these studies will have broad applicability in understanding catecholamine regulatory mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM062879-01
Application #
6319135
Study Section
Special Emphasis Panel (ZRG1-MDCN-5 (01))
Program Officer
Hagan, Ann A
Project Start
2001-05-01
Project End
2004-04-30
Budget Start
2001-05-01
Budget End
2002-04-30
Support Year
1
Fiscal Year
2001
Total Cost
$203,279
Indirect Cost
Name
University of Alabama in Tuscaloosa
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
Tuscaloosa
State
AL
Country
United States
Zip Code
35487
Wang, Zhe; Ferdousy, Faiza; Lawal, Hakeem et al. (2011) Catecholamines up integrates dopamine synthesis and synaptic trafficking. J Neurochem 119:1294-305
Bowling, Kevin M; Huang, Zhinong; Xu, Dong et al. (2008) Direct binding of GTP cyclohydrolase and tyrosine hydroxylase: regulatory interactions between key enzymes in dopamine biosynthesis. J Biol Chem 283:31449-59
Hsouna, Anita; Lawal, Hakeem O; Izevbaye, Iyare et al. (2007) Drosophila dopamine synthesis pathway genes regulate tracheal morphogenesis. Dev Biol 308:30-43
Chaudhuri, Anathbandhu; Bowling, Kevin; Funderburk, Christopher et al. (2007) Interaction of genetic and environmental factors in a Drosophila parkinsonism model. J Neurosci 27:2457-67
Stallings, Dontarie M; Hepburn, Dion D D; Hannah, Meredith et al. (2006) Nutritional supplement chromium picolinate generates chromosomal aberrations and impedes progeny development in Drosophila melanogaster. Mutat Res 610:101-13
Funderburk, Christopher D; Bowling, Kevin M; Xu, Dong et al. (2006) A typical N-terminal extensions confer novel regulatory properties on GTP cyclohydrolase isoforms in Drosophila melanogaster. J Biol Chem 281:33302-12
Zhang, Yong Q; Friedman, David B; Wang, Zhe et al. (2005) Protein expression profiling of the drosophila fragile X mutant brain reveals up-regulation of monoamine synthesis. Mol Cell Proteomics 4:278-90
Hepburn, Dion D D; Xiao, Jiarong; Bindom, Sharell et al. (2003) Nutritional supplement chromium picolinate causes sterility and lethal mutations in Drosophila melanogaster. Proc Natl Acad Sci U S A 100:3766-71