G protein-coupled receptor kinases (GRKs) are serine/threonine protein kinases best known for their ability to phosphorylate activated G protein-coupled receptors. Numerous studies have revealed that GRKs are important regulators of normal cell and organism function and contribute to a number of human diseases including cardiovascular disease, cancer and neurological disorders. While there has been significant progress in understanding GRK function, the mechanistic basis for many of the in vivo functions of GRKs remains largely unknown. During the last grant period, we initiated studies on the two C. elegans GRKs and found that they regulate a number of important biological processes including egg-laying, growth and sex determination. Interestingly, our work revealed that GRK-2 regulates serotonin metabolism and that GRK-1 and GRK-2 mediate opposing effects on egg-laying. Moreover, the serotonin metabolite 5-HIAA was found to bind to SER-1, a 5-HT2A receptor ortholog, and oppose the effects of serotonin. To further define the biological role of GRKs and provide mechanistic insight into how GRK structure correlates with in vivo function, we propose to use molecular, biochemical and cell biological strategies to better define the mechanistic basis for GRK regulation of egg-laying. Our central hypothesis is that these studies will enable us to mechanistically link GRK structure/function with important biological processes in the worm and that our findings will provide novel insight relevant to understanding the physiological and pathophysiological role of GRKs in humans. We plan to test our central hypothesis by pursuing three specific aims.
In aim 1, we will elucidate the mechanisms involved in GRK-2 regulation of egg-laying and test the hypotheses that: (A) GRK-2 regulates serotonin metabolism by regulating vesicular monoamine transporter and/or monoamine oxidase activity and (B) 5-HIAA functions as a biased SER-1 agonist.
In aim 2, we will elucidate the mechanisms involved in GRK-1 regulation of egg-laying and test the hypothesis that GRK-1 stimulates Go signaling.
In aim 3, we will use molecular and proteomic strategies to define the in vivo interactions and substrates for C. elegans GRKs. We are poised to mechanistically dissect how GRK-2 regulates serotonin metabolism, how serotonin and 5-HIAA differentially modulate serotonin receptor function and how GRK-1 and GRK-2 coordinately regulate biology. These studies will provide important insight that is highly relevant to not only understanding GRKs in the worm but also to understanding how GRKs function in humans.

Public Health Relevance

GRKs are important regulators of normal organism function and contribute to a number of human diseases including cardiovascular disease, cancer and various neurological disorders. The proposed research is relevant to public health and the NIH mission because it will elucidate the mechanisms involved in GRK function in vivo and thereby provide important insight into the pathophysiological role of GRKs in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM044944-22
Application #
8438706
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Dunsmore, Sarah
Project Start
1991-07-01
Project End
2017-04-30
Budget Start
2013-07-01
Budget End
2014-04-30
Support Year
22
Fiscal Year
2013
Total Cost
$344,100
Indirect Cost
$122,100
Name
Thomas Jefferson University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
053284659
City
Philadelphia
State
PA
Country
United States
Zip Code
19107
Kang, Dong Soo; Tian, Xufan; Benovic, Jeffrey L (2014) Role of ?-arrestins and arrestin domain-containing proteins in G protein-coupled receptor trafficking. Curr Opin Cell Biol 27:63-71
Kang, Dong Soo; Tian, Xufan; Benovic, Jeffrey L (2013) *-Arrestins and G protein-coupled receptor trafficking. Methods Enzymol 521:91-108
So, Christopher H; Michal, Allison; Komolov, Konstantin E et al. (2013) G protein-coupled receptor kinase 2 (GRK2) is localized to centrosomes and mediates epidermal growth factor-promoted centrosomal separation. Mol Biol Cell 24:2795-806
Woerner, B Mark; Luo, Jingqin; Brown, Kristin R et al. (2012) Suppression of G-protein-coupled receptor kinase 3 expression is a feature of classical GBM that is required for maximal growth. Mol Cancer Res 10:156-66
Wood, Jordan F; Wang, Jianjun; Benovic, Jeffrey L et al. (2012) Structural domains required for Caenorhabditis elegans G protein-coupled receptor kinase 2 (GRK-2) function in vivo. J Biol Chem 287:12634-44
Michal, Allison M; So, Christopher H; Beeharry, Neil et al. (2012) G Protein-coupled receptor kinase 5 is localized to centrosomes and regulates cell cycle progression. J Biol Chem 287:6928-40
So, Christopher H; Michal, Allison M; Mashayekhi, Rouzbeh et al. (2012) G protein-coupled receptor kinase 5 phosphorylates nucleophosmin and regulates cell sensitivity to polo-like kinase 1 inhibition. J Biol Chem 287:17088-99
Barker, Breann L; Benovic, Jeffrey L (2011) G protein-coupled receptor kinase 5 phosphorylation of hip regulates internalization of the chemokine receptor CXCR4. Biochemistry 50:6933-41
Patial, Sonika; Luo, Jiansong; Porter, Katie J et al. (2010) G-protein-coupled-receptor kinases mediate TNF?-induced NF?B signalling via direct interaction with and phosphorylation of I?B?. Biochem J 425:169-78
Chen, X P; Yang, W; Fan, Y et al. (2010) Structural determinants in the second intracellular loop of the human cannabinoid CB1 receptor mediate selective coupling to G(s) and G(i). Br J Pharmacol 161:1817-34

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