Rho family GTPases is ubiquitous molecular switches that control extraordinarily diverse cellular processes. They are activated by guanine nucleotide exchange factors (GEFs) that are roughly 5-fold more numerous than the GTPases themselves and integrate the many cellular inputs controlling GTPase function. GEFs and GTPases form complex networks that are constituted transiently and locally for specific purposes. Biochemical, genetic, molecular, and structural analyses have unraveled a great deal about these critically important pathways, but the most important functional property, their spatio-temporal regulation, can only be fully understood in the context of intact cells. This PPG brings together team members with diverse expertise to develop innovative technologies enabling the study of GEF/GTPase networks in vivo, computational tools to extract network architecture and signaling kinetics from imaging data, and in-depth knowledge of cell behaviors critically dependent on GEF/GTPase dynamics: (Project 1- Hahn) will deliver GEF biosensors based on designs addressing different GEF structural classes. In a collaborative effort with Sondek, expert in GEF structure, different biosensor designs will report GEF activation by specific upstream inputs, and activation of endogenous GEFs. (Project 2- Danuser) will develop the ability to simultaneously image and/or photomanipulate the activity of any pair of GEFs and GTPases, for high resolution studies of GEF/GTPase spatio-temporal coordination. New computational tools will combine data from different experiments to model large networks, and to extract network architecture and signaling kinetics from imaging data. These methods will be tested in studies of complex GEF-GTPase feedback interactions. (Project 3- Hall): This biologically focused project will extend our work to multicellular systems. We will focus on GEF activation in cell-cell junctions and cryptic lamellipodia, and identify GEFs regulating collective migration. (Project 4- Burridge) will address the role of GEF/GTPase netvvorks in mechanotransduction, exploring novel findings regarding the mechanical regulation of RhoA signaling at cell-matrix and cell-cell adhesions during initiation of protrusions, and in the nucleus.

Public Health Relevance

Little is known about how the cell uses networks of 'signaling proteins'for many purposes by controlling when and where they assemble. We will generate tools to address the dynamics of such networks in space and time within living cells, and study specific networks composed of GEFs and GTPases, ubiquitous proteins involved in many basic cell behaviors and diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
5P01GM103723-02
Application #
8744288
Study Section
Special Emphasis Panel (ZRG1-IMST-J (40))
Program Officer
Deatherage, James F
Project Start
2013-09-30
Project End
2018-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
2
Fiscal Year
2014
Total Cost
$1,101,950
Indirect Cost
$221,000
Name
University of North Carolina Chapel Hill
Department
Pharmacology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Cook, Aaron A; Deng, Wei; Ren, Jinqi et al. (2018) Calcium-induced structural rearrangements release autoinhibition in the Rap-GEF CalDAG-GEFI. J Biol Chem 293:8521-8529
Segal, Dagan; Zaritsky, Assaf; Schejter, Eyal D et al. (2018) Feedback inhibition of actin on Rho mediates content release from large secretory vesicles. J Cell Biol 217:1815-1826
Graham, David M; Andersen, Tomas; Sharek, Lisa et al. (2018) Enucleated cells reveal differential roles of the nucleus in cell migration, polarity, and mechanotransduction. J Cell Biol 217:895-914
Ma, Xiao; Dagliyan, Onur; Hahn, Klaus M et al. (2018) Profiling cellular morphodynamics by spatiotemporal spectrum decomposition. PLoS Comput Biol 14:e1006321
Zaritsky, Assaf (2018) Sharing and reusing cell image data. Mol Biol Cell 29:1274-1280
Tajadura-Ortega, Virginia; Garg, Ritu; Allen, Richard et al. (2018) An RNAi screen of Rho signalling networks identifies RhoH as a regulator of Rac1 in prostate cancer cell migration. BMC Biol 16:29
Woodham, Emma F; Paul, Nikki R; Tyrrell, Benjamin et al. (2017) Coordination by Cdc42 of Actin, Contractility, and Adhesion for Melanoblast Movement in Mouse Skin. Curr Biol 27:624-637
Zaritsky, Assaf; Tseng, Yun-Yu; Rabadán, M Angeles et al. (2017) Diverse roles of guanine nucleotide exchange factors in regulating collective cell migration. J Cell Biol 216:1543-1556
Takano, Tetsuya; Wu, Mengya; Nakamuta, Shinichi et al. (2017) Discovery of long-range inhibitory signaling to ensure single axon formation. Nat Commun 8:33
Zaritsky, Assaf; Obolski, Uri; Gan, Zhuo et al. (2017) Decoupling global biases and local interactions between cell biological variables. Elife 6:

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