During the last five years, we identified several new proteins that are components of novel G protein signaling pathways. Among them are RGS proteins that not only serve as GAPs for G proteins through their RGS domains, but also bind to other proteins through their unique N- and C-termini. We have concentrated on two RGS proteins, GAIP (RGS19), a GAP for Go_i3, and RGS-PX1, a GAP for Go_s which also has a PX domain that identifies it as it as a SNX protein involved in phosphoinositide signaling. We have obtained results indicating that RGS proteins link G protein signaling to other signaling pathways, including EGF and TrkA growth factor signaling and phosphoinositide signaling, and to other cell processes such as protein degradation. The overall goal of the proposed work is to define the molecular components of the novel signalin! networks we have uncovered and to establish their cellular location, trafficking and functions. The underlyin themes are that RGS proteins are both GAPs and bddging molecules that link signaling events and that these interactions are spatially regulated by ceHuJar distribution and trafficking. We will focus on three specific aims:
Specific Aim #1 : To assess the role of RGS-PX1 in tinking Go_s signaling and EGF receptor (EGFR) down-regulation at early endosomes. This will be accomplished by assessing the effects of activating the _2- adrenergic receptor and G(zs on EGFR degradation, MAP kinase activation, RGS-PX1 localization and, distribution of Go_s-GFP. We hypothesize that RGS-PX1 serves to link signals generated through activation of I Go_sto EGFR signaling.
Specific Aim #2 : To determine if GIPC functions to organize signaling complexes that I function in growth factor signaling and trafficking. GIPC, a PDZ protein, binds both GAIP and the TrkA growth I factor receptor. We wUi use deconvolution an(] immunoelectron microscopy, a proteomics approach and RNAi I experiments to investigate GIPC s role in assembiy of signaling and trafficking complexes.
Specific Aim #3 : I To further define Gczi3-GAIP-GIPC-GIPN signaling networks by biochemical, morphological and bioinformatics I approaches= We will concentrate here on i) isolation of putative signaling complexes containing GAIP, G(zi3,j and GPCR, ii) characterization of GIPN, a novel GAIP-interacting protein that is a putative E3 ligase, and iii) usel of bioinformatics to model God-GAIP-GIPC/GIPN signaling networks. These studies can be expected to I considerably expand knowledge of the role of RGS proteins in linking G protein and growth factor signaling. ! Due to their broad functions in regulation of cell functions, including cell growth, differentiation and mitogenesis, t RGS proteins represent attractive targets for development of pharmacologic and anti-tumor agents. 1

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
3R01CA100768-05S2
Application #
7596530
Study Section
Pharmacology A Study Section (PHRA)
Program Officer
Spalholz, Barbara A
Project Start
2003-04-17
Project End
2009-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
5
Fiscal Year
2008
Total Cost
$54,761
Indirect Cost
Name
University of California San Diego
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Aznar, Nicolas; Ear, Jason; Dunkel, Ying et al. (2018) Convergence of Wnt, growth factor, and heterotrimeric G protein signals on the guanine nucleotide exchange factor Daple. Sci Signal 11:
Midde, Krishna; Sun, Nina; Rohena, Cristina et al. (2018) Single-Cell Imaging of Metastatic Potential of Cancer Cells. iScience 10:53-65
Siddiqui, Shoib S; Springer, Stevan A; Verhagen, Andrea et al. (2017) The Alzheimer's disease-protective CD33 splice variant mediates adaptive loss of function via diversion to an intracellular pool. J Biol Chem 292:15312-15320
Ghosh, Pradipta; Rangamani, Padmini; Kufareva, Irina (2017) The GAPs, GEFs, GDIs and…now, GEMs: New kids on the heterotrimeric G protein signaling block. Cell Cycle 16:607-612
Aznar, Nicolas; Sun, Nina; Dunkel, Ying et al. (2017) A Daple-Akt feed-forward loop enhances noncanonical Wnt signals by compartmentalizing ?-catenin. Mol Biol Cell 28:3709-3723
Ghosh, Pradipta (2017) The stress polarity pathway: AMPK 'GIV'-es protection against metabolic insults. Aging (Albany NY) 9:303-314
Lizcano, Anel; Secundino, Ismael; Döhrmann, Simon et al. (2017) Erythrocyte sialoglycoproteins engage Siglec-9 on neutrophils to suppress activation. Blood 129:3100-3110
Gupta, Vijay; Bhandari, Deepali; Leyme, Anthony et al. (2016) GIV/Girdin activates G?i and inhibits G?s via the same motif. Proc Natl Acad Sci U S A 113:E5721-30
Dunkel, Ying; Diao, Kexin; Aznar, Nicolas et al. (2016) Prognostic impact of total and tyrosine phosphorylated GIV/Girdin in breast cancers. FASEB J 30:3702-3713
Barbazan, Jorge; Dunkel, Ying; Li, Hongying et al. (2016) Prognostic Impact of Modulators of G proteins in Circulating Tumor Cells from Patients with Metastatic Colorectal Cancer. Sci Rep 6:22112

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