Repellent action requires a partial, asymmetric collapse of the growth cone to effectively """"""""steer"""""""" the developing neurite to its target. Determination of the molecular events that underlie the collapse response will provide a greater understanding of neurite pathfinding, a process of fundamental importance in the development of the functional nervous system. The main goal of the proposed research is to elucidate the signaling events of semaphorin-mediated growth cone collapse. This research will 1) analyze the role of protein kinase C (PKC) signaling in the disassembly of adhesion sites required for semaphorin-induced growth cone collapse and 2) characterize the distribution and dynamics of the predominant PKC substrate in growth cones, the myristoylated, alanine-rich C kinase substrate (MARCKS). Confocal immunofluorescence microscopy and reflection interference microscopy (RIM) will be used to determine the spatial relationships between known adhesion site proteins, MARCKS, and adhesive areas within the growth cone. Biochemical isolation of growth cone adhesion sites will be used to analyze the effect of MARCKS phosphorylation on adhesion complex integrity. MARCKS dynamics within the growth cone will be characterized by observing repellent-induced changes in the distribution of a MARCKS-green fluorescent protein (GFP) fusion protein. Functional consequences of aberrant PKC signaling will be determined by observing the turning response of growth cones from DRG neurons expressing a dominant-negative, phosphorylation-deficient MARCKS mutant.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31NS044705-03
Application #
6780454
Study Section
Special Emphasis Panel (ZRG1-F03A (20))
Program Officer
Mamounas, Laura
Project Start
2002-07-01
Project End
2005-03-31
Budget Start
2004-07-01
Budget End
2005-03-31
Support Year
3
Fiscal Year
2004
Total Cost
$20,939
Indirect Cost
Name
University of Colorado Denver
Department
Biology
Type
Schools of Medicine
DUNS #
041096314
City
Aurora
State
CO
Country
United States
Zip Code
80045
Sanford, Staci D; Gatlin, Jesse C; Hokfelt, Tomas et al. (2008) Growth cone responses to growth and chemotropic factors. Eur J Neurosci 28:268-78
Hokfelt, Tomas; Stanic, Davor; Sanford, Staci D et al. (2008) NPY and its involvement in axon guidance, neurogenesis, and feeding. Nutrition 24:860-8
Gatlin, Jesse C; Estrada-Bernal, Adriana; Sanford, Staci D et al. (2006) Myristoylated, alanine-rich C-kinase substrate phosphorylation regulates growth cone adhesion and pathfinding. Mol Biol Cell 17:5115-30
Mikule, Keith; Sunpaweravong, Somkiat; Gatlin, Jesse C et al. (2003) Eicosanoid activation of protein kinase C epsilon: involvement in growth cone repellent signaling. J Biol Chem 278:21168-77