Interleukin-5 (IL-5) is a hematopoietic cytokine that specifically promotes the differentiation, survival and function of eosinophils, and is considered central to the pathophysiology of eosinophilic inflammation in allergic disorders and asthma. The IL-5 receptor (IL-5R) is a heterodimer consisting of an IL-5 specific alpha chain (IL-5Ralpha) and a common beta chain (betac) which alone does not bind IL-5, but is necessary for agonistic signal transduction and is shared with the IL-3Ralpha and GM-CSFRalpha for signaling. The overall goal of this proposal is to understand the mechanisms that regulate IL-5 signaling through the ac subunit of the IL-5R. Our previous studies delineated the functional structure of IL-5 and the binding domains within IL-5 that engage the IL-5Ralpha and betac receptor subunits. Our preliminary studies for this competitive renewal suggest that IL-5 signaling through the ac may be dependent on a conformational charge field surrounding the glu 13 residue of IL-5. Furthermore, we made the novel finding that IL-5 agonistic ligation of the IL-5R also initiates proteasome termination of IL-5 signaling that results in both homotypic and heterotypic desensitization of cells to each of the ac engaging cytokines, IL-3, IL-5, and GM-CSF.
Specific aims of this project are to: 1) Determine the residues in IL-5 that are required for functional ligation of ac; 2) Determine the molecular mechanisms that regulate proteasome termination of signaling by ac; 3) Investigate the potential for proteasome-mediated heterotypic desensitization of ac to modulate the terminal differentiation and function of IL-5 responsive cells; and 4) Explore the potential for proteasome degradation of shared cytokine receptor subunits to be a conserved physiologic mechanism for both homolypic and heterotypic desensitization of cytokine signaling.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI036936-06
Application #
6640433
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Dong, Gang
Project Start
1996-07-01
Project End
2007-06-30
Budget Start
2003-07-01
Budget End
2004-06-30
Support Year
6
Fiscal Year
2003
Total Cost
$301,000
Indirect Cost
Name
Baylor College of Medicine
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
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Martinez-Moczygemba, Margarita; Huston, David P (2010) Immune dysregulation in the pathogenesis of pulmonary alveolar proteinosis. Curr Allergy Asthma Rep 10:320-5
Martinez-Moczygemba, Margarita; Doan, Minh L; Elidemir, Okan et al. (2008) Pulmonary alveolar proteinosis caused by deletion of the GM-CSFRalpha gene in the X chromosome pseudoautosomal region 1. J Exp Med 205:2711-6
Martinez-Moczygemba, Margarita; Huston, David P; Lei, Jonathan T (2007) JAK kinases control IL-5 receptor ubiquitination, degradation, and internalization. J Leukoc Biol 81:1137-48
Ng, Bernard; Yang, Fan; Huston, David P et al. (2004) Increased noncanonical splicing of autoantigen transcripts provides the structural basis for expression of untolerized epitopes. J Allergy Clin Immunol 114:1463-70
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