Abstract

In chemotaxing cells, a polarity circuit involving PDKs and PTEN results in the accumulation of PI (3,4,5)P3 on the membrane at the cell's leading edge and serves to bias the local activity of the actin cytoskeleton. A similar circuit also plays a central role in cytokinesis. However, it is not known how signals are transmitted to PDKs and PTEN, how PI(3,4,5)P3 influences the local activity of the cytoskeleton, or which pathways act in parallel with the PI3K pathway. The answers to these questions have the potential to impact our understanding and treatment of cancer and inflammatory diseases. ? ? Dictyostelium discoideum is an excellent model system to pursue these investigations and has proved instrumental in identifying a number of """"""""lead"""""""" genes that may be involved in these processes. The lead genes include YakA, a kinase that links receptor/G-protein to PI3K and other effectors; PH-domain containing proteins; Pianissimo (PiaA), a novel cytosolic regulator of chemotaxis that interacts with DdTor; RacC which may link PI(3,4,5)P3 to the cytoskeleton; a phospholipase A2 that synergizes with the PI3K pathway; Tsunami (TsuA) and Serrated (SerA), genes that control cell polarity. Cell lines that lack these and related genes have been generated and will be used to elucidate their function. Physiological responses such as PI(3,4,5)P3 accumulation, actin polymerization, and myosin phosphorylation will be quantified in these cells and the localization of components such as PI3K, PTEN, PI(3,4,5)P3, coronin, and myosin II will be determined by live cell imaging. To explore the relationship between these genes, cell lines lacking combinations of genes will be generated and, when genetic interactions are indicated by phenotype, further biochemical and imaging analyses will be pursued. Studies will also be conducted to try and discover additional genes involved in chemotaxis and cytokinesis. Proteins that interact physically with the known components will be identified using co-immunoprecipitation and yeast 2-hybrid analyses, and suppressor screens for mutations that reverse the chemotaxis and cytokinesis phenotypes of the existing cell lines will be used identify genes that have genetic interactions. ? ?

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37GM028007-27
Application #
7083705
Study Section
Cell Structure and Function (CSF)
Program Officer
Anderson, Richard A
Project Start
1980-07-01
Project End
2010-06-30
Budget Start
2006-07-01
Budget End
2007-06-30
Support Year
27
Fiscal Year
2006
Total Cost
$583,690
Indirect Cost

  Institution

Name
Johns Hopkins University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218

  Publications

Hoeller, Oliver; Toettcher, Jared E; Cai, Huaqing et al. (2016) G? Regulates Coupling between Actin Oscillators for Cell Polarity and Directional Migration. PLoS Biol 14:e1002381
Yang, Jr-Ming; Nguyen, Hoai-Nghia; Sesaki, Hiromi et al. (2015) Engineering PTEN function: membrane association and activity. Methods 77-78:119-24
Swaney, Kristen F; Borleis, Jane; Iglesias, Pablo A et al. (2015) Novel protein Callipygian defines the back of migrating cells. Proc Natl Acad Sci U S A 112:E3845-54
Nguyen, Hoai-Nghia; Yang, Jr-Ming; Miyamoto, Takafumi et al. (2015) Opening the conformation is a master switch for the dual localization and phosphatase activity of PTEN. Sci Rep 5:12600
Nguyen, H-N; Yang Jr, J-M; Rahdar, M et al. (2015) A new class of cancer-associated PTEN mutations defined by membrane translocation defects. Oncogene 34:3737-43
Artemenko, Yulia; Lampert, Thomas J; Devreotes, Peter N (2014) Moving towards a paradigm: common mechanisms of chemotactic signaling in Dictyostelium and mammalian leukocytes. Cell Mol Life Sci 71:3711-47
Cai, Huaqing; Katoh-Kurasawa, Mariko; Muramoto, Tetsuya et al. (2014) Nucleocytoplasmic shuttling of a GATA transcription factor functions as a development timer. Science 343:1249531
Nguyen, H N; Afkari, Y; Senoo, H et al. (2014) Mechanism of human PTEN localization revealed by heterologous expression in Dictyostelium. Oncogene 33:5688-96
Tang, Ming; Wang, Mingjie; Shi, Changji et al. (2014) Evolutionarily conserved coupling of adaptive and excitable networks mediates eukaryotic chemotaxis. Nat Commun 5:5175
Nguyen, Hoai-Nghia; Yang, Jr-Ming; Afkari, Yashar et al. (2014) Engineering ePTEN, an enhanced PTEN with increased tumor suppressor activities. Proc Natl Acad Sci U S A 111:E2684-93

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