Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects

Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects

Bibliographic Details
Main Author: Beil, Elizabeth
Language:English
Published: University of Toledo Health Science Campus / OhioLINK 2012
Subjects:
Immunology
Fc&947
RIIA
immunoglobulin
phagocytosis
endocytosis
oxidative burst
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=mco1332933291
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-mco13329332912021-08-03T05:38:54Z Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects Beil, Elizabeth Immunology Fc&947 RIIA immunoglobulin phagocytosis endocytosis oxidative burst <p>FcγRIIA, a transmembrane receptor for immunoglobulin G (IgG), triggers phagocytosis, endocytosis and oxidative burst in leukocytes. Signal transduction via FcγRIIA leading to these outcomes has been relatively well studied. To identify additional signaling partners, a yeast two-hybrid analysis employing the cytoplasmic domain of FcγRIIA was performed. Interestingly, the SH2 domain of signal transducer and activator of transcription 6 (STAT6) appeared in our analysis. STAT6 traditionally interacts with interleukin-4 (IL-4) receptors to induce expression of IL-4 and IL-13 in T cells. Macrophages have also been observed to produce IL-4 in response to pharmaceutical and pathogenic stimuli and to respond to IL-4. However, production of IL-4 or IL-13 subsequent to FcγR ligation has not been observed. Therefore, to better define the specific interaction of FcγRIIA with STAT6, we engineered Chinese hamster ovary cells to express FcγRIIA and RFP-STAT6 to determine if specific ligation of FcγRIIA induces STAT6 nuclear translocation. This resulted in lack of consistent expression of the RFP-STAT6 causing us to perform our subsequent experiments in the human macrophage-like cell line, THP-1. To further elucidate this interaction, FcγRIIA immunoprecipitation followed by western blotting of FcγRIIA and the whole cell lysates from THP-1 macrophages, was performed. We observed the constitutive interaction of non-phosphorylated STAT6 with FcγRIIA. We subsequently sought to examine STAT6 activation after stimulation of THP-1 macrophages with various FcγR ligands. Using IL-4 as a positive control, we observed heat-aggregated IgG induces significant amounts of STAT6 translocation compared to untreated cells (p<0.05). We then sought to determine if IL-4 was produced from THP-1 macrophages after FcγR ligation. We were unable to detect IL-4 from THP-1 macrophages, but were able to detect IL-4 from Jurkat cells, a human T cell line, that were stimulated with ionomycin and phorbol myristal acetate. We then examined the effects of IL-4 on FcγR-mediated activities. We observed that transient exposure of THP-1 macrophages to IL-4 had no significant effect on endocytosis or phagocytosis.</p> <p>Our current observations indicate an interaction exists between FcγRIIA and STAT6 through the SH2 domain of STAT6 producing nuclear translocation of non-phosphorylated STAT6 without induction of IL-4 gene expression. This observance may signal an important avenue of research in understanding the mechanisms of phosphorylation of STAT6 and STAT6 induced gene expression.</p> 2012-05-16 English text University of Toledo Health Science Campus / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=mco1332933291 http://rave.ohiolink.edu/etdc/view?acc_num=mco1332933291 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Immunology
Fc&947
RIIA
immunoglobulin
phagocytosis
endocytosis
oxidative burst
spellingShingle Immunology
Fc&947
RIIA
immunoglobulin
phagocytosis
endocytosis
oxidative burst
Beil, Elizabeth
Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
author Beil, Elizabeth
author_facet Beil, Elizabeth
author_sort Beil, Elizabeth
title Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
title_short Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
title_full Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
title_fullStr Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
title_full_unstemmed Identification of fcγRIIA STAT6 Interaction and the Subsequent Effects
title_sort identification of fcγriia stat6 interaction and the subsequent effects
publisher University of Toledo Health Science Campus / OhioLINK
publishDate 2012
url http://rave.ohiolink.edu/etdc/view?acc_num=mco1332933291
work_keys_str_mv AT beilelizabeth identificationoffcgriiastat6interactionandthesubsequenteffects
_version_ 1719423009189527552

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