The efficient coordination of signal transduction at the plasma membrane is dependent on the segregation, or organization, of sets of signaling proteins in specific microdomains. The overall aim of this study is to dissect the function and composition of the plasma membrane microdomains that are involved in Ras signaling pathways. Ras proteins operate as molecular witches in many signal transduction pathways and are frequently mutated in human tumors. The highly homologous Ras isoforms, H-ras, N-ras, and K-ras, generate different signal out puts most likely because their different C-terminal membrane anchors direct the proteins to different microdomains of the plasma membrane. This project will analyze the protein and lipid content of these micro domains using Ras isoforms as molecular markers. Novel biochemical and electron microscopic techniques will be used to examine the plasma membrane distribution of the different Ras isoforms, to compare their distribution to known activators and effectors, and to reconstitute the dynamics of Ras laterals segregation in vitro. The study will also examine to what extent compartmentalized plasma membrane proteins and lipids contribute to Ras microlocalization and function. Transgenic and knock-out mice will be used to define the role of caveolae in H-ras and K-ras function.This description of the precise molecular environment in which specific Ras isoforms operate may identify novel targets for selective chemotherapy.
The specific aims of the project are: 1. A proteomic and lipidomic characterization of Ras surface micro domains 2. An electron microscopic visualization and characterization of surface micro domains 3. An investigation of the dynamic regulation of micro domain localization of Ras and Ras-interacting proteins in response to physiological stimuli.
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|Ariotti, Nicholas; Fernández-Rojo, Manuel A; Zhou, Yong et al. (2014) Caveolae regulate the nanoscale organization of the plasma membrane to remotely control Ras signaling. J Cell Biol 204:777-92|
|Gambin, Yann; Ariotti, Nicholas; McMahon, Kerrie-Ann et al. (2014) Single-molecule analysis reveals self assembly and nanoscale segregation of two distinct cavin subcomplexes on caveolae. Elife 3:e01434|
|Zhang, Feng; Wang, Ziqing; Lu, Maryia et al. (2014) Temporal production of the signaling lipid phosphatidic acid by phospholipase D2 determines the output of extracellular signal-regulated kinase signaling in cancer cells. Mol Cell Biol 34:84-95|
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|Hocker, Harrison J; Cho, Kwang-Jin; Chen, Chung-Ying K et al. (2013) Andrographolide derivatives inhibit guanine nucleotide exchange and abrogate oncogenic Ras function. Proc Natl Acad Sci U S A 110:10201-6|
|Cho, Kwang-Jin; Park, Jin-Hee; Hancock, John F (2013) Staurosporine: A new tool for studying phosphatidylserine trafficking. Commun Integr Biol 6:e24746|
|Collins, Brett M; Davis, Melissa J; Hancock, John F et al. (2012) Structure-based reassessment of the caveolin signaling model: do caveolae regulate signaling through caveolin-protein interactions? Dev Cell 23:11-20|
|Janosi, Lorant; Li, Zhenlong; Hancock, John F et al. (2012) Organization, dynamics, and segregation of Ras nanoclusters in membrane domains. Proc Natl Acad Sci U S A 109:8097-102|
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