A Role of Calcineurin in Coreceptor Regulation during Differentiation of Cd4+Cd8+T Cells

Kuwata, Takeshi; Asada, Akiko; Ohoka, Yoshiharu; Mukai, M; Miyaike, Mitsuko; Iwata, Makoto

doi:10.1006/bbrc.1998.8767

Cited by 6 publications

(11 citation statements)

References 31 publications

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“…The CD4 ϩ CD8 ϩ lymphoma RLm6 becomes CD4 SP by incubation with the same combination of IM/PMA, and differentiation or transition of the cells is also inhibited by FK506 (38). Furthermore, RLm6 transfected with an expression vector encoding an active form of CN became CD4 SP upon stimulation with PMA alone (38). These findings collectively suggest that CN plays a pivotal role in Ca 2ϩ signaling for positive selection.…”

Section: Discussionmentioning

confidence: 81%

“…Rapamycin, another immunosuppressant that binds to FKBP12 without affecting CN activity, fails to inhibit differentiation (data not shown) or to annul the anti-apoptotic effect (10). The CD4 ϩ CD8 ϩ lymphoma RLm6 becomes CD4 SP by incubation with the same combination of IM/PMA, and differentiation or transition of the cells is also inhibited by FK506 (38). Furthermore, RLm6 transfected with an expression vector encoding an active form of CN became CD4 SP upon stimulation with PMA alone (38).…”

Section: Discussionmentioning

confidence: 95%

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Successive Expression and Activation of NFAT Family Members during Thymocyte Differentiation

Adachi¹,

Amasaki²,

Miyatake³

et al. 2000

Journal of Biological Chemistry

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Differentiation of immature CD4؉ CD8 ؉ thymocytes to mature CD4 ؉ or CD8 ؉ T cells is induced by positive selection and appears to involve calcineurin-dependent activation of NFAT, a family of transcription factors. NFATx is predominantly expressed in CD4 ؉ CD8 ؉ thymocytes, whereas NFATp and NFATc are expressed at much lower levels in the thymus than in mature T cells. However, how or when each NFAT member is involved in the differentiation pathway is unclear. Using an in vitro model system where isolated CD4 ؉ CD8؉ thymocytes can survive and differentiate into semi-mature CD4-lineage T cells, we suggest that low calcineurin activity sustained for approximately 20 h is required for cell survival and differentiation. Accordingly, the DNA binding activity of NFAT slowly increased during the stimulation of 20 h to induce the differentiation. NFATx significantly contributed to the early rise, but the late increase was mostly due to NFATc activation. Meanwhile, the expression of NFATx mRNA decreased and that of NFATc mRNA increased. The DNA-binding activity of NFATp was detectable but low throughout the stimulation. NFATp became dominantly active after the semi-mature T cells differentiated into mature and activated CD4 T cells. These findings suggest that NFATx and NFATc successively play roles in T cell development.

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Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 95%

Successive Expression and Activation of NFAT Family Members during Thymocyte Differentiation

Adachi¹,

Amasaki²,

Miyatake³

et al. 2000

Journal of Biological Chemistry

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“…RLm6 cells, an x-ray-induced CD4 ϩ CD8 ϩ T cell leukemia line from BALB/c mice, were cultured in complete Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and antibiotics (29). RLm6-⌬CN, an RLm6 transfectant expressing the Ca 2ϩ -independent form of calcineurin, was obtained as previously described (26).…”

Section: Methodsmentioning

confidence: 99%

“…Wild-type or mutant NFATx cDNAs were ligated to the pMKIT-Neo expression vector, and the resultant plasmids were transfected into the RLm6 T cell line, representing the CD4 ϩ CD8 ϩ stage of thymocytes. RLm6 is an x-ray-induced CD4 ϩ CD8 ϩ T cell line (29) that becomes CD4 single-positive (26) and acquires the CC chemokine receptor CCR7 (36) upon calcium ionophore ionomycin/PMA stimulation. pMKITmNFATx, pMKITmNFATx-⌬(CRI), and pMKITmNFATx-⌬(CRI⅐SP12) were used for generating stable transfectants, and 5, 6, and 10 gentamycin-resistant clones were obtained, respectively ( Table I).…”

Section: Differentiation Of Cd4mentioning

confidence: 99%

“…This indicates that the role of NFATx in thymocytes is to up-regulate Bcl-2 expression in response to the selecting signal to facilitate thymocyte survival. RLm6 (RL male 6) cells, a CD4 ϩ CD8 ϩ T lymphoma, and CD4 ϩ CD8 ϩ thymocytes differentiate into CD4 single-positive cells upon phorbol 12-myristate 13-acetate (PMA) and calcium ionophore treatment (26,27). We show that when the constitutively nuclear NFATx mutant was introduced into this cell line, differentiation into the CD4 single-positive stage was induced in the presence of PMA alone, suggesting that NFATx plays an important role in the positive selection by regulating the expression pattern of CD4 and CD8 co-receptors.…”

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A Constitutively Nuclear Form of NFATx Shows Efficient Transactivation Activity and Induces Differentiation of CD4+CD8+ T Cells

Amasaki

Adachi

Ishida

et al. 2002

Journal of Biological Chemistry

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The Ca 2؉ signal facilitates nuclear translocation of NFAT through the dephosphorylation of clustered serine residues in the calcium regulatory domain by the Ca 2؉ /calmodulin-dependent phosphatase calcineurin. The conformation of dephosphorylated NFAT exposes the nuclear localization signal for translocation into the nucleus and masks the nuclear export sequence to keep the protein in the nucleus. It has been reported that deletion of some serine-rich motifs masking the nuclear localization signal results in the translocation of NFAT into the nucleus, but that the nuclear export sequence located at the N terminus also needs to be deleted for NFATx (NFAT4/NFATc3) to exert efficient transactivation function. Here, we report that deletion of the critical serine-rich motifs of NFATx leads to a conformation that efficiently exposes the nuclear localization signal and that has stronger transcription activity compared with the fully activated wild-type protein in the presence of the nuclear export sequence. This also suggests that the regulation of the transactivation domain by phosphorylation observed in NFAT1 may not contribute significantly to the transcription activity of NFATx. The expression of this constitutively nuclear form of NFATx in the CD4 ؉ CD8 ؉ T cell line facilitates differentiation into the CD4 single-positive stage upon stimulation with phorbol ester. Our data suggest that NFATx is involved in the regulation of co-receptor expression during differentiation into the CD4 single-positive stage.One of the outputs of the proximal signaling pathways of the T cell antigen receptor is activation of phospholipase C␥1. Phospholipase C␥1 catalyzes phosphatidylinositol 4,5-bisphosphate to produce inositol 1,4,5-triphosphate and diacylglycerol (1). Inositol 1,4,5-triphosphate is a crucial messenger molecule in up-regulating cytoplasmic Ca 2ϩ concentrations, whereas diacylglycerol activates the small G protein Ras through binding to the Ras guanyl nucleotide-releasing protein, the hematopoietic cell-specific guanine nucleotide exchange factor, via the diacylglycerol-binding domain and has a role as a protein kinase C activator (2). Protein kinase C also contributes to the activation of Ras. The up-regulation of cytoplasmic calcium leads to the activation of various Ca 2ϩ /calmodulin-dependent enzymes, including the phosphatase calcineurin. One of the crucial targets of calcineurin is NFAT (nuclear factor of activated T cells) family members (3, 4). Dephosphorylation of NFAT family proteins results in nuclear translocation (5-7). The activation of Ras and the downstream mitogen-activated protein kinase cascade leads to the activation of AP-1 (activator protein-1). Many genes including those of various cytokines are induced by the collaborative activity of NFAT and AP-1.NFAT transcription activity is regulated by several steps. One important step is the regulation of intracellular localization. NFAT family members harbor two conserved nuclear localization signals (NLS), 1 one in the calcium regulatory domain and th...

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Current Pathways for Immune Manipulation

Lees

Azimzadeh

Ding

et al. 2014

Textbook of Organ Transplantation

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A Role of Calcineurin in Coreceptor Regulation during Differentiation of Cd4+Cd8+T Cells

Cited by 6 publications

References 31 publications

Successive Expression and Activation of NFAT Family Members during Thymocyte Differentiation

Successive Expression and Activation of NFAT Family Members during Thymocyte Differentiation

A Constitutively Nuclear Form of NFATx Shows Efficient Transactivation Activity and Induces Differentiation of CD4+CD8+ T Cells

Current Pathways for Immune Manipulation

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