Biomedical subjects

M Atsuta

Publications and source records attributed to M Atsuta.

At least 73 records · Page 4Linked to original sources

PubMed1999

Characterization and inhibitory effect of antibacterial dental resin composites incorporating silver-supported materials.

Resin composites with antibacterial activity may be useful for preventing the secondary caries frequently seen around restorations. The purposes of this study were to investigate antibacterial light-activated dental resin composites incorporating each of two silver-supported antibacterial materials and evaluate their long-lasting inhibitory effect against Streptococcus mutans. Two types of silver-supported antibacterial materials, Novaron (N) and Amenitop (AM) were used. These antibacterial materials were incorporated into TEGDMA-UDMA-based light-activated resin composites, and the antibacterial activities and mechanical properties of these composites, and also the release of silver ions, were examined. Two silver-supported antibacterial materials inhibited the growth of the major oral pathogen S. mutans. The minimum inhibitory concentration in suspensions of N and AM against S. mutans was 40 microg/mL and 30 microg/mL, respectively. Composites incorporating 5 wt % (N-5) or more of Novaron and 7 wt % (AM-7) or more of Amenitop inhibited the growth of S. mutans after immersion in water for 6 months. There was no or extremely little release of silver ions from the N-5 and AM-7 composites after 1 day or after 6 months of immersion in water. No significant difference in either compressive or flexural strength was observed between the control and the N-5 composites after 1 day or after 6 months of storage in water. However, for the AM-5 composite, there was a significant difference in both strength parameters between the two immersion periods. These results indicate that a light-activated dental resin composite incorporating silver-supported antibacterial material such as Novaron may be useful clinically because of its long-lasting inhibitory effect against S. mutans and its favorable mechanical properties.

Anti-Bacterial Agents↗

PubMed1999

CD28-independent costimulation of T cells by OX40 ligand and CD70 on activated B cells.

OX40 and its ligand (OX40L) have been implicated in T cell-dependent humoral immune responses. To further characterize the role of OX40/OX40L in T-B cell interaction, we newly generated an anti-mouse OX40L mAb (RM134L) that can inhibit the costimulatory activity of OX40L transfectants for anti-CD3-stimulated T cell proliferation. Flow cytometric analyses using RM134L and an anti-mouse OX40 mAb indicated that OX40 was inducible on splenic T cells by stimulation with immobilized anti-CD3 mAb in a CD28-independent manner, while OX40L was not expressed on resting or activated T cells. OX40L was inducible on splenic B cells by stimulation with anti-IgM Ab plus anti-CD40 mAb, but not by either alone. These activated B cells exhibited a potent costimulatory activity for anti-CD3-stimulated T cell proliferation and IL-2 production. Anti-CD80 and anti-CD86 mAbs partially inhibited the costimulatory activity, and further inhibition was obtained by their combination with RM134L and/or anti-CD70 mAb. We also found the anti-IgM Ab- plus anti-CD40 mAb-stimulated B cells exhibited a potent costimulatory activity for proliferation of and IL-2 production by anti-CD3-stimulated CD28- T cells from CD28-deficient mice, which was substantially inhibited by RM134L and/or anti-CD70 mAb. These results indicated that OX40L and CD70 expressed on surface Ig- and CD40-stimulated B cells can provide CD28-independent costimulatory signals to T cells.

Animals↗

PubMed1999

A study on cytochrome c oxidoreductase for bonding a tri-n-butylborane-initiated luting agent to dentin.

The purpose of this study was to investigate the effectiveness of cytochrome c, an oxidoreductase, in terms of initiation of polymerization in dentin bonding. The efficacy of experimental dentin primers was evaluated via the bonding of a luting agent to dentin. The eight primers evaluated were cytochrome c aqueous solutions, four with 35 wt% 2-hydroxyethyl methacrylate (HEMA) and four without. The concentrations of cytochrome c in the primers were 0, 0.01, 0.1, and 1[corrected] micromol/g. The luting agent (Super-Bond C&B) consisted of methyl methacrylate (MMA), 4-methacryloyloxyethyl trimellitate anhydride (4-META), and tri-n-butylborane (TBB) initiator. Bovine dentin surfaces were flattened, etched with an aqueous solution of 10 wt% phosphoric acid, primed, and then bonded with stainless steel rods. After 1-day immersion in water, tensile testing revealed that the bond strength was influenced by the application of cytochrome c and HEMA. The maximum bond strength of 24.6 MPa was recorded with aqueous HEMA primer containing 10 micromol/g cytochrome c. This bonding technique, combining oxidoreductase with Super-Bond C&B, may potentially be applied for seating resin-bonded restorations.

Animals↗

PubMed1999

Thin sol-gel-derived silica coatings on dental pure titanium casting.

The sol-gel dipping process, in which liquid silicon alkoxide is transformed into a solid silicon-oxygen network, can produce a thin film coating of silica (SiO(2)). The features of this method are high homogeneity and purity of the thin SiO(2) film and a low sinter temperature, which are important in the preparation of coating films that can protect metallic ion release from the metal substrate and prevent attachment of dental plaque. We evaluated the surface properties of dental pure titanium casting coated with a thin SiO(2) or SiO(2)/F-hybrid film by the sol-gel dipping process. The metal specimens were pretreated by dipping in isopropylalcohol solution containing 10 wt% 3-aminopropyl trimethoxysilane and treated by dipping in the silica precursor solution for 5 min, withdrawal at a speed of 2 mm/min, air-drying for 20 min at room temperature, heating at 120 degrees C for 20 min, and then storing at room temperature. Both SiO(2) and SiO(2)/F films bonded strongly (above 55 MPa) to pure titanium substrate by a tensile test. SiO(2(-)) and SiO(2)/F-coated specimens immersed in 1 wt% of lactic acid solution for two weeks showed significantly less release of titanium ions (30. 5 ppb/cm(2) and 9.5 ppb/cm(2), respectively) from the substrate than noncoated specimens (235.2 ppb/cm(2)). Hydrophobilization of SiO(2(-)) and SiO(2)/F-coated surfaces resulted in significant increases of contact angle of water (81.6 degrees and 105.7 degrees, respectively) compared with noncoated metal specimens (62.1 degrees ). The formation of both thin SiO(2) and SiO(2)/F-hybrid films by the sol-gel dipping process on the surface of dental pure titanium casting may be useful clinically in enhancing the bond strength of dental resin cements to titanium, preventing titanium ions release from the substrate, and reducing the accumulation of dental plaque attaching to intraoral dental restorations.

Adhesiveness↗

PubMed1999

Silica coatings formed on noble dental casting alloy by the sol-gel dipping process.

The sol-gel dipping process, in which liquid silicon alkoxide is transformed into the solid silicon-oxygen network, can produce a thin film coating of silica (SiO2). The features of this method are high homogeneity and purity of the thin SiO2 film and a low sinter temperature, which are important in preparation of coating films that can protect from metallic ion release from the metal substrate and prevent attachment of dental plaque. We evaluated the surface characteristics of the dental casting silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy coated with a thin SiO2 film by the sol-gel dipping process. The SiO2 film bonded strongly (over 40 MPa) to Ti-implanted Ag-Pd-Cu-Au alloy substrate as demonstrated by a pull test. Hydrophobilization of Ti-implanted/SiO2-coated surfaces resulted in a significant increase of the contact angle of water (80.5 degrees) compared with that of the noncoated alloy specimens (59.3 degrees). Ti-implanted/SiO2-coated specimens showed the release of many fewer metallic ions (192 ppb/cm2) from the substrate than did noncoated specimens (2,089 ppb/cm2). The formation of a thin SiO2 film by the sol-gel dipping process on the surface of Ti-implanted Ag-Pd-Cu-Au alloy after casting clinically may be useful for minimizing the possibilities of the accumulation of dental plaque and metal allergies caused by intraoral metal restorations.

Adhesiveness↗

PubMed1999

Perforin-dependent NK cell cytotoxicity is sufficient for anti-metastatic effect of IL-12.

IL-12 exerts a potent anti-tumor effect, which is possibly mediated by multiple mechanisms including activation of NK and NKT cells, induction of cytotoxic T lymphocytes, and inhibition of angiogenesis. In the present study, we characterized the cytotoxic effector cells and mechanisms responsible for the anti-metastatic effect of IL-12. Administration of IL-12 had a comparable inhibitory effect on experimental lung metastasis of B16 melanoma cells in wild-type C57BL/6 mice and RAG-2-/- mice that lack T and NKT cells, which was abolished by depletion of NK cells. Cytotoxic activity of liver and splenic mononuclear cells against B16 was induced by IL-12 administration in RAG-2-/- mice at a level comparable to that in wild-type mice, which was also abolished by depletion of NK cells. Moreover, the anti-metastatic effect of IL-12 was abrogated by perforin deficiency, but not by Fas ligand deficiency, in association with a lack of IL-12-induced cytotoxic activity of liver and splenic mononuclear cells against B16. These results suggest that perforin-dependent cytotoxicity of IL-12-activated NK cells is sufficient for the anti-metastatic effect of IL-12.

Animals↗

PubMed1999

Effectiveness of polymerization of a prosthetic composite using three polymerization systems.

STATEMENT OF PROBLEM: Although properties of laboratory-polymerized composite materials are influenced by the type of polymerizing unit, little information is available regarding the comparison between use of a high-intensity light source and application of secondary heat treatment. PURPOSE: This study examined properties of a prosthetic veneering composite polymerized with 3 polymerizing systems to evaluate the effects of varying polymerization modes on hardness, solubility, and depth of cure. MATERIAL AND METHODS: A composite material designed for a prosthetic veneer (Conquest Crown and Bridge) was polymerized using 3 methods: (1) exposure in the proprietary photopolymerizing unit with 2 halogen lamps (Cure-Lite Plus), followed by heating in an oven (Conquest Automatic Curing Unit); (2) exposure in a photopolymerizing unit with a xenon stroboscopic light source (Dentacolor XS); and (3) exposure in a photopolymerizing unit with 2 metal halide lamps (Hyper LII). Knoop hardness, water solubility, and depth of cure were determined for groups of 5 specimens, according to standardized testing methods. Data were compared using analysis of variance and the Duncan new multiple range test (P <.05). RESULT: The hardness number generated with the metal halide unit was statistically greater than those produced by the other 2 methods, and material component released into water was minimal when the material was exposed with the metal halide unit (P <.05). Among the 3 photopolymerizing units, the metal halide unit consistently exhibited the greatest depth of cure. CONCLUSION: Certain properties generated with the use of the high-intensity polymerizing unit exceeded those obtained from a proprietary system that requires a postheat treatment.

Analysis of Variance↗

PubMed1999

Effect of noble metal conditioners on bonding between prosthetic composite material and silver-palladium-copper-gold alloy.

STATEMENT OF PROBLEM: Mechanical retentive devices and the application of complicated surface preparation have been indispensable for bonding composite material to the metal substructure of restorations. PURPOSE: This study evaluated the priming effects of 4 metal conditioners on bonding between a prosthetic veneering material and a silver-palladium-based casting alloy. MATERIAL AND METHODS: Four primers designed for conditioning noble metal alloys (Alloy Primer, Metaltite, Metal Primer II, and V-Primer) were assessed (all materials contain organic sulfur compounds). Cast disk specimens made of silver-palladium-copper-gold alloy (Castwell M.C.12) were primed with 1 of the 4 primers, and bonded with a light-activated prosthetic composite material (Axis). Shear testing was performed before and after thermocycling for evaluation of bond durability. RESULTS: All primed groups showed improved 24-hour bond strengths compared with the unprimed group. After thermocycling, 3 groups primed with the Metal Primer II, Alloy Primer, and Metaltite agents exhibited the highest bond strength. CONCLUSION: Use of 1-liquid metal conditioners containing sulfur compounds was a simple and useful method for improving bonding between the alloy and the composite material tested.

Composite Resins↗

PubMed1999

Effect of MMA-PMMA resin polymerization initiators on the bond strengths of adhesive primers for noble metal.

OBJECTIVES: This study was conducted to investigate the effect of MMA-PMMA resin polymerization initiators on the bond strengths of two adhesive metal primers by evaluating the shear bond strengths of resins of silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy. METHODS: Three types of MMA-PMMA resins for which the polymerization initiators were TBB, BPO-amine and CQ-amine, and two adhesive primers, Metal PrimerII and V-Primer, were used. A brass ring placed over the nonprimed or primed casting alloy disk surface was filled with each resin. The half specimens were stored in water at 37 degrees C for 24 h. In addition, another half specimens were then immersed alternately in water baths at 4 degrees C and 60 degrees C for 1 min each for 20,000 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min. RESULTS: There were no significant differences (p > 0.05) in bond strength between the three types of resins with or without thermal cycling when Metal PrimerII was used. However, when Ag-Pd-Cu-Au alloy was primed with V-Primer, the bond strength of CQ-amine resin was significantly weaker than that of TBB resin. Metal PrimerII was more effective for enhancing the bond strength and the bond strength was not affected by thermal cycling, in contrast to V-Primer. SIGNIFICANCE: The effectiveness of Metal PrimerII to enhance the bond strength is not influenced by polymerization mode of MMA-PMMA resin, in contrast to V-Primer when the resin is bonded to Ag-Pd-Cu-Au alloy.

Adhesives↗

PubMed1999

Properties of fluoride-releasing light-activated resin cement.

OBJECTIVES: Fluoroaluminosilicate glass and poly(acrylic acid) in small water phase was incorporated into resin composite cements to reduce or prevent secondary caries around luted restorations. The purpose of this study was to investigate the physical properties and the amounts of fluoride released from four types of visible light-activated resin cements. METHODS: A powder was composed of silanized SiO2 filler and 4.5 wt.% (G-4.5), 9.5 wt.% (G-9.5) or 19.5 wt.% (G-19.5) fluoroaluminosilicate glass and 0.5 wt.% reducing agent. The 45.25 wt.% triethylene glycol dimethacrylate (TEGDMA), 45.25 wt.% 2-hydroxyethyl methacrylate (HEMA), 9 wt.% poly(acrylic acid) solution in water and 0.5 wt.% camphorquinone were contained in a liquid. The powder and liquid were mixed at a 3:1 ratio by weight and the three types of specimen disks were cured using a photo-curing lamp. The TEGDMA-based composite cement was used as control (G-0). The specimens were immersed in water at 37 degrees C for 24 h or 6 months and compressive strength (CS) and diametral tensile strength (DTS) were evaluated for the four experimental materials. Disks prepared from the four resin cements were also immersed in deionized distilled water at 37 degrees C, and the fluoride released was measured over a period of 24 weeks. RESULTS: G-9.5 specimens showed almost the same CS and DTS as G-4.5 and G-0 specimens and significantly higher values for both parameters than G-19.5 specimens after 6 months of water storage. The amount of fluoride released from the three fluoride-containing resin cements continued to increase over the entire experimental period. The fluoride release rates of G-9.5 and G-19.5 resin cements were almost the same and were significantly greater than that of the G-4.5 resin cement. SIGNIFICANCE: G-9.5 containing 9.5 wt.% fluoroaluminosilicate glass may be a clinically useful resin cement due to its favorable physical properties and fluoride release.

Analysis of Variance↗

PubMed1999

Antibacterial activity of resin composites with silver-containing materials.

Resin composites with antibacterial activity may be useful to decrease the frequency of secondary caries around restorations. The purposes of this study were to investigate the antibacterial activity of light-activated resin composites incorporating one of three silver-containing materials and to evaluate their long-term inhibitory effect against Streptococcus mutans The three types of silver-containing materials, Novaron (N), Amenitop (AM), and AIS, were incorporated into TEGDMA-UDMA-based light-activated resin composites, and the antibacterial activities, mechanical properties and release of silver ions were examined. Minimum inhibitory concentrations in suspensions of N, AM, and AIS against S. mutans were 1.1, 1.2, and 23.0 mg/ml, respectively. Resin composites incorporating 5 wt% of Novaron (N-5) and 7 wt% of Amenitop (AM-7) inhibited the growth of S. mutans after immersion in water for 3 months, whereas the resin composite incorporating 10 wt% of AIS did not. No significant difference in either compressive or flexural strength was observed between the control and N-5 composites after 1 d and 3 months storage in water. However, for AM-5 composite, there was a significant difference in both strength parameters between the two immersion periods. There was no or extremely little release of silver ions from the N-5 and AM-5 composites after 1 d or 3 months immersion in water. These results indicated that a light-activated resin composite incorporating silver-containing materials such as Novaron may be clinically useful due to its long-term inhibitory effect against S. mutans and favorable mechanical properties.

Aluminum Oxide↗

PubMed1999

Adhesive primers for bonding cobalt-chromium alloy to resin.

This study evaluated the effect of five adhesive primers on the shear bond strength of a self-curing resin to cobalt-chromium (Co-Cr) alloy. The adhesive primers Acryl Bond (AB, Shofu), Cesead Opaque Primer (COP, Kuraray), Metacolor Opaque Bonding Liner (MOBL, Sun-Medical), Metal PrimerII (MPII, GC) and MR. Bond (MRB, Tokuyama) were used. A brass ring which was placed over the casting alloy disk surface non-primed or primed with each primer was filled with the self-curing MMA-PMMA resin. The specimens were stored in water at 37 degrees C for 24 h and then immersed alternately in water baths at 4 C and 60 degrees C for 1 min each for up to 50000 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min. All of the primers examined, except MOBL, improved the shear bond strength between the resin and Co-Cr alloy compared with nonprimed specimens prior to thermal cycling. Regardless of which primer was used, the shear bond strength significantly differed between thermal cycles 0 and 50000. However, after 50000 thermal cycles, the bond strengths of resin to Co-Cr alloy primed with COP or MPII were significantly greater than those of specimens primed with AB, MOBL or MRB and non-primed controls. This study indicated that COP and MPII are effective primers to obtain higher bond strength between resin and Co-Cr alloy.

Adhesives↗

PubMed1999

Curing depth of prosthetic composite materials polymerized with their proprietary photo-curing units.

This study examined curing depth of eight prosthetic composite materials polymerized by means of six photo-curing units for the purpose of evaluating the curing performance of material-curing unit combinations. Each composite material was exposed with a photo-curing unit recommended by the manufacturer. The light sources of the units were halogen/fluorescent, xenon, metal halide, fluorescent, and halogen lamps, and exposure periods were 20, 30, 60, and 90 s. Curing depth of the materials was determined according to the method described by the International Organization for Standardization (ISO 4049). The results were analysed by factorial analysis of variance (ANOVA) and multiple comparison intervals. Two-factor ANOVA revealed that the depth of cure was influenced both by the material-unit combination and by the exposure period (P = 0.0001). Among the eight combinations, a hybrid composite material (Prywood color) polymerized with a metal halide curing unit (Hyper LII) exhibited the greatest depth of cure after 90-s exposure. For all combinations, longer exposure increased the depth of cure.

Chemical Phenomena↗

PubMed1999

Effect of three-liquid bonding agents on bond strength to a machine-milled ceramic material.

This study determined the bond strengths of porcelain bonding systems joined to a ceramic material, with the aim of evaluating the effect of a catalyst for silane coupling as well as that of initiators for bonding agents. Two sizes of specimen were cut from ceramic blocks (Cerec 2 Vitablocs Mark II) and then primed with either a three-liquid self-curing bonding agent (Clearfil Porcelain Bond, CPB), a three-liquid dual-activated bonding agent (Clapearl Bonding Agent, CBA), or their components. Unprimed specimens were also used as controls. After conditioning, the two different sized plates were bonded together with a dual-cured luting agent (Clapearl DC). The specimens were stored in 37 degrees C water for 24 h and shear bond strengths were determined. Shear testing revealed that the greatest bond strength was generated in the group consisting of ceramic material primed with CBA and exposed for 20 s prior to luting. Bond strengths of the CPB-primed group and the CBA-primed group without pre-exposure were comparable, whereas the remaining groups resulted in significantly lower bond strengths than the other three groups. The priming effect was greatly enhanced when a catalyst was used with the silane coupler as compared with the application of silane alone. The results suggest that incorporation of an initiator and a catalyst for silane coupling into the bonding agent reciprocally enhances bonding between the luting agent and the ceramic material.

Analysis of Variance↗

PubMed1999

Depth of cure of prosthetic composite materials polymerized with laboratory and handheld photo-curing units.

This study examined depth of cure of two prosthetic composite materials (Artglass(R) and Dentacolor(R)) polymerized by means of four photo-curing units for the purpose of comparing the curing performance of laboratory and handheld curing units. Each composite material was photo-exposed either with one of two laboratory photo-curing units (Dentacolor XS(R) and UniXS(R)) or with one of two handheld photo-curing units (Translux CL(R) and Translux EC(R)). The light sources were differently shaped xenon stroboscopic lamps for the laboratory units, and halogen lamps of differing intensity for the handheld units. Exposure periods were 20, 30, 60, and 90 s, and depth of cure of the materials was determined with a scraping technique. The two handheld curing units generated significantly greater depth of cure for both materials than either of the two laboratory curing units. Of the two laboratory units, the Dentacolor XS(R) unit produced somewhat greater depth of cure for all combinations than the UniXS(R) unit, whereas the differences in depth of cure of the two materials exposed with the two handheld units were not significant when the exposure time period was 60 s or more. The Dentacolor(R) composite generally demonstrated greater depth of cure than the Artglass(R) composite under identical curing conditions.

Chemical Phenomena↗

PubMed1999

Adhesive bonding of noble metal alloys with a triazine dithiol derivative primer and an adhesive resin.

The purpose of this study was to evaluate the bond strength and durability of a metal adhesive system bonded to noble metal alloys. Disc specimens were cast from type IV gold (type IV, Casting Gold M. C., metal-ceramic gold (Au-Pt-Pd, Degudent Universal, metal-ceramic palladium (Pd-Ga-Co, PTM 88 silver-indium (Ag-In-Zn, Salivan Hard and silver-palladium-copper-gold (Ag-Pd-Cu, S12) alloys and pure silver (pure Ag). The specimens were air-abraded with 50 micron alumina, conditioned with a thiol-based primer designed for noble alloys (V-Primer), and then bonded with an adhesive resin (Super-Bond Opaque Ivory). Shear bond strengths were determined after repeated thermocycling (4-60 degrees C, 1 min each, 100 000 cycles). The average bond strengths in MPa (n=8) were 30.9 for the type IV alloy, 29.0 for the Ag-Pd-Cu alloy, 28.0 for the Au-Pt-Pd alloy, 26.3 for the pure Ag, 26.0 for the Pd-Ga-Co alloy and 9.3 for the Ag-In-Zn alloy. The Ag-In-Zn alloy exhibited significantly lower bond strength than the other alloys, whereas the bond strengths of the other four alloys and pure Ag were comparable (P<0.05). It is concluded that the combined use of the thiol derivative primer and the adhesive resin is effective for bonding the noble metal alloys examined, with the exception of the Ag-In-Zn alloy.

Adhesives↗

PubMed1998

Identification of rat OX40 ligand by molecular cloning.

OX40 (CD134) is a member of the tumor necrosis factor (TNF) receptor superfamily first identified as a rat T cell activation marker. In the present study, we identified the rat ligand for OX40 (OX40L) by molecular cloning. Rat OX40L cDNA was cloned from a HTLV-1-transformed rat T cell line by cross-hybridization with mouse OX40L cDNA. The predicted rat OX40L polypeptide is composed of 199 amino acids, showing 80.9 and 43.3% homology to mouse and human OX40L, respectively. Expression of rat OX40L mRNA was found in HTLV-1-transformed rat T cell lines. Expression of OX40L on the cell surface of these HTLV-1-transformed rat T cell lines was also demonstrated by flow cytometric analysis with a soluble fusion protein composed of the extracellular region of the Fc portion of human IgG (OX40-Ig). To explore the function of rat OX40L, we generated cDNA transfectants stably expressing rat OX40L. The rat OX40L transfectants exhibited a potent costimulatory activity for proliferation and IL-2 production of anti-CD3-stimulated rat T cells. These results indicated that rat OX40L can provide an efficient costimulation for rat T cells and that it may be involved in HTLV-1-associated pathologies in the rat system as has been suggested in the human system.

Amino Acid Sequence↗

PubMed1998

CD27, a member of the tumor necrosis factor receptor superfamily, activates NF-kappaB and stress-activated protein kinase/c-Jun N-terminal kinase via TRAF2, TRAF5, and NF-kappaB-inducing kinase.

CD27 is a member of the tumor necrosis factor (TNF) receptor superfamily and is expressed on T, B, and NK cells. The signal via CD27 plays pivotal roles in T-T and T-B cell interactions. Here we demonstrate that overexpression of CD27 activates NF-kappaB and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK). Deletion analysis of the cytoplasmic domain of CD27 revealed that the C-terminal PIQEDYR motif was indispensable for both NF-kappaB and SAPK/JNK activation and was also required for the interaction with TNF receptor-associated factor (TRAF) 2 and TRAF5, both of which have been implicated in NF-kappaB activation by members of the TNF-R superfamily. Co-transfection of a dominant negative TRAF2 or TRAF5 blocked NF-kappaB and SAPK/JNK activation induced by CD27. Recently, a TRAF2-interacting kinase has been identified, termed NF-kappaB-inducing kinase (NIK). A kinase-inactive mutant NIK blocked CD27-, TRAF2-, and TRAF5-mediated NF-kappaB and SAPK/JNK activation. These results indicate that TRAF2 and TRAF5 are involved in NF-kappaB and SAPK/JNK activation by CD27, and NIK is a common downstream kinase of TRAF2 and TRAF5 for NF-kappaB and SAPK/JNK activation.

Calcium-Calmodulin-Dependent Protein Kinases↗