The Ras - ERK MAP kinase signaling pathway is critical for establishing cell fates during development. Importantly, mutations that activate the Ras pathway are a prevalent cause of human tumors. A major gap in our current understanding of this pathway is how activation of ERK alters the balance in gene expression to promote cell proliferation. Our long term goal is to understand how the Ras signaling pathway switches the activity of transcription factors so that they promote cell proliferation. We will address this by analyzing transcription factors that respond to Ras-mediated signaling in C. elegans and vertebrates. Understanding how the Ras pathway controls gene expression in development and disease in an important objective of medical research, since the information may lead to new and effective therapies for tumors caused by activated Ras signaling. Our preliminary results have defined exciting new mechanisms for the regulation of the LIN-1 transcription factor by Ras-mediated signaling and support two innovative hypotheses. (1) The LIN-1 transcription factor is post translationally modified by SUMO. Sumoylated LIN-1 represses transcription by interacting with MEP-1, DAS-1 and MAS-1, proteins involved in chromatin remodeling. (2) Activated ERK switches LIN-1 from a sumoylated, transcriptional represser that inhibits cell proliferation to a phosphorylated, transcriptional activator that induces cell proliferation. To test these hypotheses, we propose three specific aims.
Aims 1 and 2: We will use biochemical techniques to define domains and specific residues of MEP-1, MAS-1 and DAS-1 that interact with LIN-1. We will characterize the relevance and specific functions of these interactions in intact animals. These studies will define the mechanisms of SUMO-mediated transcriptional repression and the significance of one DNA binding transcription factor recruiting three different transcriptional repressers.
Aim 3 : We will determine how ERK switches the activity of LIN-1. These studies will elucidate the mechanisms and logic of a switch that is critical for cell fate determination during development. The results of these studies will significantly advance the understanding of how ETS transcription factors are regulated, how SUMO mediates transcriptional repression, and how ERK promotes cell proliferation, and address critical gaps in our current knowledge of these important areas. This switch may also respond to oncogenic signaling pathways, and these studies will provide information that can result in new therapeutic strategies for blocking the proliferation of tumor cells in humans. Lay language: This research will reveal how tumor cells proliferate and suggest new strategies for treating human cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA084271-10
Application #
7890558
Study Section
Cellular Signaling and Dynamics Study Section (CSD)
Program Officer
Hildesheim, Jeffrey
Project Start
2000-01-01
Project End
2012-07-31
Budget Start
2010-08-23
Budget End
2012-07-31
Support Year
10
Fiscal Year
2010
Total Cost
$253,560
Indirect Cost
Name
Washington University
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Leight, Elizabeth R; Murphy, John T; Fantz, Douglas A et al. (2015) Conversion of the LIN-1 ETS protein of Caenorhabditis elegans from a SUMOylated transcriptional repressor to a phosphorylated transcriptional activator. Genetics 199:761-75
Roh, Hyun Cheol; Collier, Sara; Deshmukh, Krupa et al. (2013) ttm-1 encodes CDF transporters that excrete zinc from intestinal cells of C. elegans and act in a parallel negative feedback circuit that promotes homeostasis. PLoS Genet 9:e1003522
Roh, Hyun Cheol; Collier, Sara; Guthrie, James et al. (2012) Lysosome-related organelles in intestinal cells are a zinc storage site in C. elegans. Cell Metab 15:88-99
Murphy, John T; Bruinsma, Janelle J; Schneider, Daniel L et al. (2011) Histidine protects against zinc and nickel toxicity in Caenorhabditis elegans. PLoS Genet 7:e1002013
Johnson, Kenneth G; Kornfeld, Kerry (2010) The CRAL/TRIO and GOLD domain protein TAP-1 regulates RAF-1 activation. Dev Biol 341:464-71
Liu, Zhenyi; Schneider, Daniel L; Kornfeld, Kerry et al. (2010) Simple copy number determination with reference query pyrosequencing (RQPS). Cold Spring Harb Protoc 2010:pdb.prot5491
Bruinsma, Janelle J; Schneider, Daniel L; Davis, Diana E et al. (2008) Identification of mutations in Caenorhabditis elegans that cause resistance to high levels of dietary zinc and analysis using a genomewide map of single nucleotide polymorphisms scored by pyrosequencing. Genetics 179:811-28
Leight, Elizabeth R; Glossip, Danielle; Kornfeld, Kerry (2005) Sumoylation of LIN-1 promotes transcriptional repression and inhibition of vulval cell fates. Development 132:1047-56
Miley, Ginger R; Fantz, Douglas; Glossip, Danielle et al. (2004) Identification of residues of the Caenorhabditis elegans LIN-1 ETS domain that are necessary for DNA binding and regulation of vulval cell fates. Genetics 167:1697-709
Hsu, Virginia; Zobel, Cheri L; Lambie, Eric J et al. (2002) Caenorhabditis elegans lin-45 raf is essential for larval viability, fertility and the induction of vulval cell fates. Genetics 160:481-92

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