Cdc42p plays a key role in the polarization of cells towards a variety of signals (e.g., T cell polarization towards antigen-presenting cells, fibroblast polarization towards wound sites, or yeast bud formation). Human CDC42 can functionally substitute for its yeast counterpart, suggesting that key functions of Cdc42p have been highly conserved, and the ability to apply genetic, biochemical, and cell biological approaches makes yeast a very powerful system for delineating the mechanism of Cdc42p action in cell polarization. In this system, a cell-cycle signal provided by a cyclin-dependent kinase triggers the polarization of Cdc42p, which in turn promotes the polarization of the actin cytoskeleton, the assembly of a ring of septin filaments, and the targeting of secretion towards the designated patch. The goal of the proposed research is to understand how Cdc42p polarization is regulated, and how the process is restricted so that cells only form one polarization """"""""front"""""""". Cancer cells display alterations of cell shape, cell-cell adhesion, and cell motility (all actin-dependent processes regulated by Cdc42p), which are likely to be important for numerous aspects of malignant transformation. Deregulation of Cdc42p in mammalian cells promotes anchorage-independent growth, and is necessary for the morphological changes (as well as anchorage independence) that occur in Ras- transformed cells. Thus, Cdc42p deregulation affects the proliferation as well as the metastatic potential of cancer cells. Understanding the normal regulation and function of Cdc42p is an important first step towards addressing how their misregulation might promote cancer.

Public Health Relevance

The research concerns the basic mechanisms responsible for cell polarity in eukaryotic cells. Cell polarity enables cell migration, a key aspect of metastatic malignancy. Therefore, understanding how polarity is established and regulated may reveal weak links that can be attacked by cancer therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM062300-12
Application #
8286898
Study Section
Cell Structure and Function (CSF)
Program Officer
Gindhart, Joseph G
Project Start
2001-03-01
Project End
2013-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
12
Fiscal Year
2012
Total Cost
$328,726
Indirect Cost
$118,004
Name
Duke University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
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Woods, Benjamin; Kuo, Chun-Chen; Wu, Chi-Fang et al. (2015) Polarity establishment requires localized activation of Cdc42. J Cell Biol 211:19-26
Ramirez, Samuel A; Raghavachari, Sridhar; Lew, Daniel J (2015) Dendritic spine geometry can localize GTPase signaling in neurons. Mol Biol Cell 26:4171-81

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