Alternative Splicing Factor/Splicing Factor 2 Regulates the Expression of the ζ Subunit of the Human T Cell Receptor-associated CD3 Complex

Moulton, Vaishali R.; Tsokos, George C.

doi:10.1074/jbc.m109.091660

Cited by 47 publications

(61 citation statements)

References 42 publications

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“…The TCR-associated CD3ζ chain expression is decreased in T cells from patients with SLE (8). Moreover, we previously showed that SF2/ASF regulates the expression of the CD3ζ chain in human T cells (13). Here we asked whether SF2/ASF expression is altered in patients with SLE.…”

Section: Sf2/asf Expression Levels Are Decreased In T Cells From Patimentioning

confidence: 99%

“…Alternative splicing of the CD45 isoforms was shown to be regulated by SF2/ASF using a minigene model system (24). We recently showed that SF2/ASF regulates the alternative splicing of the CD3ζ 3′UTR in primary human T cells (13). However, the role of SF2/ASF in human T lymphocyte function and specifically in autoimmune disease has never been studied.…”

mentioning

confidence: 99%

“…We previously showed that forced expression of the CD3ζ chain into SLE T cells restored these signaling defects and, more importantly, enhanced IL-2 production (12). We recently found that the serine arginine (SR) protein splicing factor 2/alternative splicing factor (SF2/ASF, aka SFRS1 or SRSF1) binds to the 3′UTR of CD3ζ and limits production of an unstable splice variant of the CD3ζ mRNA, thus enhancing the expression of CD3ζ chain in human T cells (13). Based on these observations, we hypothesized that SF2/ASF expression levels may be altered in SLE T cells and may influence T-cell function, specifically IL-2 production.…”

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confidence: 99%

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Splicing factor SF2/ASF rescues IL-2 production in T cells from systemic lupus erythematosus patients by activating IL-2 transcription

Moulton

Grammatikos

Fitzgerald

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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T cells from patients with systemic lupus erythematosus (SLE) produce insufficient amounts of the vital cytokine IL-2. We previously showed that SLE T cells express decreased levels of the T-cell receptor-CD3ζ chain and forced expression of CD3ζ into SLE T cells restores IL-2 production. We recently showed that the serine arginine protein splicing factor 2/alternative splicing factor (SF2/ASF) enhances the expression of CD3ζ chain by limiting the production of an unstable splice variant. Here we demonstrate that SF2/ASF levels are decreased in patients with SLE and more so in those with active disease. More importantly, we reveal a function of SF2/ASF, independent of T-cell receptor/CD3 signaling, whereby it is recruited to the IL-2 promoter, increases transcriptional activity, and enhances IL-2 production in SLE T cells. Our results demonstrate that SF2/ASF regulates IL-2 production and that decreased SF2/ASF expression in SLE T cells contributes to deficient IL-2 production.

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Section: Sf2/asf Expression Levels Are Decreased In T Cells From Patimentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Splicing factor SF2/ASF rescues IL-2 production in T cells from systemic lupus erythematosus patients by activating IL-2 transcription

Moulton

Grammatikos

Fitzgerald

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…SDS-PAGE and Immunoblotting-Whole T cell lysates obtained from SLE patients and healthy controls were analyzed by SDS-PAGE and subsequent immunoblotting as described previously (17). Phosphorylated SP-1 protein was visualized using an anti-SP-1 antibody kindly provided by B. KahnPerles (Marseille, France (18)) that specifically detects SP-1 phosphorylated at its serine 59.…”

Section: Methodsmentioning

confidence: 99%

Transcriptional Activation of the cAMP-responsive Modulator Promoter in Human T Cells Is Regulated by Protein Phosphatase 2A-mediated Dephosphorylation of SP-1 and Reflects Disease Activity in Patients with Systemic Lupus Erythematosus

Juang

Rauen

Wang

et al. 2011

Journal of Biological Chemistry

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Systemic lupus erythematosus (SLE) is a complex autoimmune disease with numerous abnormalities recorded at the cellular, molecular, and genetic level. Expression of the basic leucine zipper transcription factor cAMP-responsive element modulator (CREM)␣ was reported to be abnormally increased in T cells from SLE patients. CREM␣ suppresses IL-2 and T cell receptor chain gene transcription by direct binding to the respective promoters. Here, we show that increased CREM expression is the result of enhanced promoter activity. DNA binding analyses reveal direct binding of transcription factor specificity protein-1 (SP-1) to the CREM promoter resulting in enhanced transcriptional activity and increased CREM expression. Protein phosphatase 2A is known to activate SP-1 through dephosphorylation at its serine residue 59. Our results show that nuclei from SLE T cells contain lower levels of Ser 59 -phosphorylated SP-1 protein and a stronger SP-1 binding to the CREM promoter. We conclude that protein phosphatase 2A accounts for enhanced SP-1 dephosphorylation at Ser 59 in SLE T cells. More importantly, CREM promoter activity mirrors reliably disease activity in SLE patients, underscoring its potential role as a biomarker for the prediction of flares in SLE patients. Systemic lupus erythematosus (SLE)3 is a chronic inflammatory disease characterized by an autoimmune process affecting every organ, including joints, kidneys, skin, and the central nervous system (1). T cells have been demonstrated to be important in the pathogenesis of SLE (2). Functional abnormalities in SLE T cells are largely underwritten by altered gene transcription, and recent studies have revealed a vast number of transcription factors in SLE T cells displaying changes in their expression levels and function. Among them, the ␣-isoform of the transcriptional regulator cAMP-responsive element modulator (CREM) has emerged as a potent regulator of target genes that are crucially involved in T cell physiology, e.g. interleukin (IL)-2, T cell receptor chain, and transcription factor c-fos (3-5).The CREM protein family constitutes a group of transcription factors that belong to the superfamily of basic domain/ leucine zipper domain proteins such as cAMP-responsive element-binding protein (CREB) and activating transcription factors. All of them share high structural similarities and possess the ability to bind specifically cis-regulatory DNA sequences as homo-or heterodimers. The target motifs are palindromic DNA sequences denoted cAMP response elements (CRE, TGACGTCA) as well as the 5Ј-TGAC half-sites of this palindrome, both of which are highly conserved within numerous promoters of eukaryotic genes (6). Increased intracellular cAMP levels stimulate a multitude of kinases, e.g. calmodulin kinase IV, that subsequently phosphorylate and thereby activate CREM (7).Previous studies from our group have provided evidence that CREM␣ expression is increased in T cells from SLE patients (8). We have shown that CREM␣ binds to the Ϫ180 site of the IL-2 promoter in SLE T c...

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“…Interestingly, a previous report has demonstrated that CD3 chain mRNA in T cells exists as two isoforms: a full sequence form and a specific 3Ј UTR-deleted form that influences mRNA stability, leading to mRNA degradation (43). Interestingly, we have evidence that ectopic expression of NSrp70 reduces the expression of the CD3 chain in Jurkat T cells.…”

Section: Discussionmentioning

confidence: 50%

Nuclear Speckle-related Protein 70 Binds to Serine/Arginine-rich Splicing Factors 1 and 2 via an Arginine/Serine-like Region and Counteracts Their Alternative Splicing Activity

Kim

Choi

et al. 2016

Journal of Biological Chemistry

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Nuclear speckles are subnuclear storage sites containing pre-mRNA splicing machinery. Proteins assembled in nuclear speckles are known to modulate transcription and pre-mRNA processing. We have previously identified nuclear speckle-related protein 70 (NSrp70) as a novel serine/arginine (SR)-related protein that co-localizes with classical SR proteins such as serine/arginine-rich splicing factor 1 (SRSF1 or ASF/SF2) and SRSF2 (SC35). NSrp70 mediates alternative splice site selection, targeting several pre-mRNAs, including CD44 exon v5. Here we demonstrated that NSrp70 interacts physically with two SR proteins, SRSF1 and SRSF2, and reverses their splicing activity in terms of CD44 exon v5 as exon exclusion. The NSrp70 RS-like region was subdivided into three areas. Deletion of the first arginine/serine-rich-like region (RS1) completely abrogated binding to the SR proteins and to target mRNA and also failed to induce splicing of CD44 exon v5, suggesting that RS1 is critical for NSrp70 functioning. Interestingly, RS1 deletion also resulted in the loss of NSrp70 and SR protein speckle positioning, implying a potential scaffolding role for NSrp70 in nuclear speckles. NSrp70 contains an N-terminal coiled-coil domain that is critical not only for self-oligomerization but also for splicing activity. Consistently, deletion of the coiled-coil domain resulted in indefinite formation of nuclear speckles. Collectively, these results demonstrate that NSrp70 acts as a new molecular counterpart for alternative splicing of target RNA, counteracting SRSF1 and SRSF2 splicing activity.The mammalian cell nucleus contains non-membranous subnuclear bodies such as the nucleolus, Cajal bodies, promyelocytic leukemia bodies, and nuclear speckles. These bodies are generally classified by the presence of a distinct group of proteins and RNAs within them (1, 2). Nuclear speckles are irregular, punctuate structures that vary in size and shape at the immunofluorescence microscope level and are located in interchromatin regions of the nucleoplasm of mammalian cells (3,4). Several reports have demonstrated that nuclear speckles serve as storage/assembly sites for pre-mRNA splicing machinery and, therefore, elaborately regulate gene expression (2). Nuclear speckles are known to be functional centers that spatially organize transcriptional and posttranscriptional mechanisms of gene regulation. RNA-binding proteins involved in transcription and pre-mRNA processing, such as small nuclear ribonucleoprotein and arginine/serine-rich family factors (SR protein, SR-related protein), are associated with nuclear speckles (5, 6). Remarkably, two classical SR proteins, SRSF1 and SRSF2, are well known components of nuclear speckles. These SR proteins modulate both constitutive and alternative splicing by assembly of the mature spliceosome (7,8).In a previous report, we identified a novel SR-related protein, nuclear speckle-related protein 70 (NSrp70), that modulates alternative splicing site selection of several mRNAs in vivo, including Tra2␤1 v2, Fas v6, and...

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Alternative Splicing Factor/Splicing Factor 2 Regulates the Expression of the ζ Subunit of the Human T Cell Receptor-associated CD3 Complex

Cited by 47 publications

References 42 publications

Splicing factor SF2/ASF rescues IL-2 production in T cells from systemic lupus erythematosus patients by activating IL-2 transcription

Splicing factor SF2/ASF rescues IL-2 production in T cells from systemic lupus erythematosus patients by activating IL-2 transcription

Transcriptional Activation of the cAMP-responsive Modulator Promoter in Human T Cells Is Regulated by Protein Phosphatase 2A-mediated Dephosphorylation of SP-1 and Reflects Disease Activity in Patients with Systemic Lupus Erythematosus

Nuclear Speckle-related Protein 70 Binds to Serine/Arginine-rich Splicing Factors 1 and 2 via an Arginine/Serine-like Region and Counteracts Their Alternative Splicing Activity

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