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Schnurri-3 (KRC) interacts with c-Jun to regulate the IL-2 gene in T cells.

Oukka M, Wein MN, Glimcher LH - J. Exp. Med. (2004)

Bottom Line: In the immune system, AP-1 activity is highest in T cells, suggesting that a subset of T cell-specific coactivator proteins exist to selectively potentiate AP-1 function.Here, we describe that the expression of Schnurri-3, also known as kappa recognition component (KRC), is induced upon T cell receptor signaling in T cells and functions to regulate the expression of the interleukin 2 (IL-2) gene.KRC physically associates with the c-Jun transcription factor and serves as a coactivator to augment AP-1-dependent IL-2 gene transcription.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA.

ABSTRACT
The activator protein 1 (AP-1) transcription factor is a key participant in the control of T cell proliferation, cytokine production, and effector function. In the immune system, AP-1 activity is highest in T cells, suggesting that a subset of T cell-specific coactivator proteins exist to selectively potentiate AP-1 function. Here, we describe that the expression of Schnurri-3, also known as kappa recognition component (KRC), is induced upon T cell receptor signaling in T cells and functions to regulate the expression of the interleukin 2 (IL-2) gene. Overexpression of KRC in transformed and primary T cells leads to increased IL-2 production, whereas dominant-negative KRC, or loss of KRC protein in KRC- mice, results in diminished IL-2 production. KRC physically associates with the c-Jun transcription factor and serves as a coactivator to augment AP-1-dependent IL-2 gene transcription.

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KRC overexpression increases, whereas KRC loss decreases endogenous IL-2 production. (A) Jurkat T cells were stably transfected with vector (pEF) or KRC expression plasmids. Stable clones were stimulated for 18 h with 50 ng/ml PMA plus 2 μM ionomycin, and IL-2 production was measured by ELISA. (B) Primary CD4+ T cells were activated for 36 h and subsequently transduced with control (RV), KRC, or KRC dominant-negative (ZAS2) bicistronic GFP-expressing retroviruses. GFP-positive cells were sorted and stimulated for 24 h with anti-CD3 or anti-CD3/anti-CD28 antibodies and IL-2 production was measured by ELISA. (C) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3 (1.0 μg/ml)/CD28 (0.5 μg/ml) antibodies for 24 h, and IL-2 production was measured by ELISA. (D) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3/CD28 antibodies for 72 h in the presence of 200 U/ml of human IL-2. IFNγ production was measured by ELISA. Data shown are representative of four independent experiments with similar results.
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fig2: KRC overexpression increases, whereas KRC loss decreases endogenous IL-2 production. (A) Jurkat T cells were stably transfected with vector (pEF) or KRC expression plasmids. Stable clones were stimulated for 18 h with 50 ng/ml PMA plus 2 μM ionomycin, and IL-2 production was measured by ELISA. (B) Primary CD4+ T cells were activated for 36 h and subsequently transduced with control (RV), KRC, or KRC dominant-negative (ZAS2) bicistronic GFP-expressing retroviruses. GFP-positive cells were sorted and stimulated for 24 h with anti-CD3 or anti-CD3/anti-CD28 antibodies and IL-2 production was measured by ELISA. (C) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3 (1.0 μg/ml)/CD28 (0.5 μg/ml) antibodies for 24 h, and IL-2 production was measured by ELISA. (D) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3/CD28 antibodies for 72 h in the presence of 200 U/ml of human IL-2. IFNγ production was measured by ELISA. Data shown are representative of four independent experiments with similar results.

Mentions: IL-2 promoter activation requires antigen receptor engagement plus an accessory signal usually supplied by an antigen-presenting cell (22). Agents that bypass these receptors, such as PMA and ionomycin, can mimic T cell activation in the human T cell lymphoma Jurkat. To assess the function of KRC in T cells, Jurkat cells, which express barely detectable levels of endogenous KRC protein by Western blot analysis, were stably transfected with a plasmid encoding full-length KRC (pEF-KRC) or with vector-only control (pEF). G418 drug-resistant Jurkat clones were expanded and analyzed for IL-2 secretion after activation. Clones stably expressing KRC showed clear increases in KRC protein levels, as detected by Western blotting (unpublished data). We observed that all clones expressing pEF-KRC produced substantially greater amounts of IL-2 upon PMA and ionomycin treatment than activated Jurkat clones transfected with the control vector (Fig. 2 A). KRC overexpression alone was not sufficient to induce IL-2 secretion because no IL-2 was detected in the culture supernatants of unstimulated KRC-overexpressing clones (unpublished data). These results suggested that KRC is able to boost IL-2 secretion in concert with signals emanating from the TCR.


Schnurri-3 (KRC) interacts with c-Jun to regulate the IL-2 gene in T cells.

Oukka M, Wein MN, Glimcher LH - J. Exp. Med. (2004)

KRC overexpression increases, whereas KRC loss decreases endogenous IL-2 production. (A) Jurkat T cells were stably transfected with vector (pEF) or KRC expression plasmids. Stable clones were stimulated for 18 h with 50 ng/ml PMA plus 2 μM ionomycin, and IL-2 production was measured by ELISA. (B) Primary CD4+ T cells were activated for 36 h and subsequently transduced with control (RV), KRC, or KRC dominant-negative (ZAS2) bicistronic GFP-expressing retroviruses. GFP-positive cells were sorted and stimulated for 24 h with anti-CD3 or anti-CD3/anti-CD28 antibodies and IL-2 production was measured by ELISA. (C) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3 (1.0 μg/ml)/CD28 (0.5 μg/ml) antibodies for 24 h, and IL-2 production was measured by ELISA. (D) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3/CD28 antibodies for 72 h in the presence of 200 U/ml of human IL-2. IFNγ production was measured by ELISA. Data shown are representative of four independent experiments with similar results.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1887724&req=5

fig2: KRC overexpression increases, whereas KRC loss decreases endogenous IL-2 production. (A) Jurkat T cells were stably transfected with vector (pEF) or KRC expression plasmids. Stable clones were stimulated for 18 h with 50 ng/ml PMA plus 2 μM ionomycin, and IL-2 production was measured by ELISA. (B) Primary CD4+ T cells were activated for 36 h and subsequently transduced with control (RV), KRC, or KRC dominant-negative (ZAS2) bicistronic GFP-expressing retroviruses. GFP-positive cells were sorted and stimulated for 24 h with anti-CD3 or anti-CD3/anti-CD28 antibodies and IL-2 production was measured by ELISA. (C) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3 (1.0 μg/ml)/CD28 (0.5 μg/ml) antibodies for 24 h, and IL-2 production was measured by ELISA. (D) CD4 T cells from KRC+/+ or −/− mice were stimulated with anti-CD3/CD28 antibodies for 72 h in the presence of 200 U/ml of human IL-2. IFNγ production was measured by ELISA. Data shown are representative of four independent experiments with similar results.
Mentions: IL-2 promoter activation requires antigen receptor engagement plus an accessory signal usually supplied by an antigen-presenting cell (22). Agents that bypass these receptors, such as PMA and ionomycin, can mimic T cell activation in the human T cell lymphoma Jurkat. To assess the function of KRC in T cells, Jurkat cells, which express barely detectable levels of endogenous KRC protein by Western blot analysis, were stably transfected with a plasmid encoding full-length KRC (pEF-KRC) or with vector-only control (pEF). G418 drug-resistant Jurkat clones were expanded and analyzed for IL-2 secretion after activation. Clones stably expressing KRC showed clear increases in KRC protein levels, as detected by Western blotting (unpublished data). We observed that all clones expressing pEF-KRC produced substantially greater amounts of IL-2 upon PMA and ionomycin treatment than activated Jurkat clones transfected with the control vector (Fig. 2 A). KRC overexpression alone was not sufficient to induce IL-2 secretion because no IL-2 was detected in the culture supernatants of unstimulated KRC-overexpressing clones (unpublished data). These results suggested that KRC is able to boost IL-2 secretion in concert with signals emanating from the TCR.

Bottom Line: In the immune system, AP-1 activity is highest in T cells, suggesting that a subset of T cell-specific coactivator proteins exist to selectively potentiate AP-1 function.Here, we describe that the expression of Schnurri-3, also known as kappa recognition component (KRC), is induced upon T cell receptor signaling in T cells and functions to regulate the expression of the interleukin 2 (IL-2) gene.KRC physically associates with the c-Jun transcription factor and serves as a coactivator to augment AP-1-dependent IL-2 gene transcription.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA.

ABSTRACT
The activator protein 1 (AP-1) transcription factor is a key participant in the control of T cell proliferation, cytokine production, and effector function. In the immune system, AP-1 activity is highest in T cells, suggesting that a subset of T cell-specific coactivator proteins exist to selectively potentiate AP-1 function. Here, we describe that the expression of Schnurri-3, also known as kappa recognition component (KRC), is induced upon T cell receptor signaling in T cells and functions to regulate the expression of the interleukin 2 (IL-2) gene. Overexpression of KRC in transformed and primary T cells leads to increased IL-2 production, whereas dominant-negative KRC, or loss of KRC protein in KRC- mice, results in diminished IL-2 production. KRC physically associates with the c-Jun transcription factor and serves as a coactivator to augment AP-1-dependent IL-2 gene transcription.

Show MeSH
Related in: MedlinePlus