Phosphatases are important regulators of intracellular signaling events, and their functions have been implicated in many biological processes. Dual-specificity phosphatases (DUSPs), whose family currently contains 25 members, that can dephosphorylate both tyrosine serine/threonine residues substrates. The archetypical DUSP, DUSP1/MKP1, was initially discovered to regulate the activities MAP kinases by dephosphorylating TXY motif kinase domain. However, although DUSPs were more than a decade...

Calcineurin, a Ca2+/calmodulin-dependent phosphoprotein phosphatase found in several tissues, is highly concentrated mammalian brain.In an attempt to identify endogenous brain substrates for calcineurin, kinetic analyses of the dephosphorylation well-characterized phosphoproteins purified from were performed.The proteins studied were: Gsubstrate, substrate cyclic GMP-dependent protein kinase; DARPP-32, AMPdependent Protein K.-F., nucleotide-and Ca2+-independent and synapsin I, (site I)...

Studies on the interaction of calcineurin with its activator, calmodulin, showed that 1:l complex is activated species.Concomitant activation, a time-dependent deactivation phosphatase was observed.The process followed first order kinetics and dependent presence both Ca2+ calmodulin.The rate constant at pH 7.6 30 "C 0.06 min", which increased by substrate, p-nitrophenylphosphate ( K , = 11 mM), to 0.47 min".PPI nucleotides inhibited enzyme competitively accelerated deactivation.The 2.3 min-'...

The PA200 proteasome activator is a broadly expressed nuclear protein.Although how normally functions not fully understood, it has been suggested to be involved in the repair of DNA double-strand breaks (DSBs).The gene (Psme4) composed 45 coding exons spanning 108 kb on mouse chromosome 11.We generated null allele (PA200 ⌬ ) through Cre-loxP-mediated interchromosomal recombination after targeting loxP sites at either end locus.PA200 ⌬/⌬ mice are viable and have no obvious developmental...

c-Myc induces widely varying cellular effects, including cell proliferation and death. These different effects are determined, in part, by protein expression levels, which regulated through several transcriptional post-transcriptional pathways. transcripts can be detected cells at all stages of B T lymphocyte development. However, little is known about expression, how it varies, developing lymphocytes. Here mice have been generated the endogenous locus has modified (c-Myc(G)) so that encodes...

Kinetic studies on the activation of cyclic nucleotide phosphodiesterase (3',5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17) as a function calmodulin and Ca2+ concentrations have been carried out. A general approach to analyzing mechanism activation, which takes into consideration various interactions among liganded with differing degrees, is presented. The method applicable other calmodulin-regulated enzyme systems. Our kinetic analysis reveals that all four must be bound for...

A rearranged T cell receptor (TCR) Vα and Jα gene from a cytochrome c- specific hybridoma was introduced into the genomic region. The TCR α chain is expressed in majority of CD3 positive CD4 CD8 double-negative immature thymocytes. However, only few percent double-positive single-positive thymocytes express this chain. This decrease caused by rearrangement locus, which deletes gene. Analysis mice carrying transgenic β original revealed that selection efficiently rescues loss In with...

The Mre11-Rad50-Nbs1 (MRN) complex functions in the repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) at postreplicative stages cell cycle. During HR, MRN directly DSBs and initiation DSB responses through activation ataxia telangiectasia-mutated (ATM) serine-threonine kinase. Whether damage before replication G0/G1 phase cells has been less clear. In developing G1-phase lymphocytes, are generated Rag endonuclease repaired during assembly antigen receptor genes...

Objectives. The major risk factor for OA is ageing; however, the mechanisms remain largely unclear. We investigated effects and of advanced glycation end products (AGEs) that accumulate in aged joints chondrocytes. Methods. Porcine chondrocytes or cartilage fragments were prepared. Gene expression MMPs a disintegrin metalloproteinase with thrombospondin motifs (ADAMTS) was assessed by real-time RT–PCR. Gelatin zymography used to determine MMP-13 enzyme activity. Histochemistry immunoblotting...

T cell activation is dependent upon phosphorylation of MAPKs, which play a critical role in the regulation immune responses. Dual-specificity phosphatase 14 (DUSP14; also known as MKP6) classified MAPK phosphatase. The vivo functions DUSP14 remain unclear. Thus, we generated DUSP14-deficient mice and characterized roles deficiency cells resulted enhanced proliferation increased cytokine production activation. directly interacted with TGF-β-activated kinase 1 (TAK1)-binding protein (TAB1)...

The differentiation and activation of T cells are critically modulated by MAP kinases, which in turn feed-back regulated dual-specificity phosphatases (DUSPs) to determine the duration magnitude kinase activation. DUSP4 (also known as MKP2) is a kinase-induced DUSP member that dynamically expressed during thymocyte differentiation. We generated DUSP4-deficient mice study function T-cell development Our results show activation-induced phosphorylation were comparable between WT mice....

Ataxia-telangiectasia mutated (ATM)–deficient lymphocytes exhibit defects in coding joint formation during V(D)J recombination vitro. Similar vivo should affect both T and B cell development, yet the lymphoid phenotypes of ATM deficiency are more pronounced compartment. In this regard, ATM-deficient mice a preferential lymphopenia have an increased incidence nontransformed transformed cells with receptor α/δ locus translocations. We demonstrate that there is increase accumulation unrepaired...

Abstract The Ag receptor of the T lymphocyte is composed an αβ heterodimer. Both α- and β-chains are products somatic rearrangement V(D)J segments encoded on respective loci. During cell development, β-chain precedes α-chain rearrangement. mechanism allelic exclusion ensures expression a single in each cell, whereas large number cells express two functional α-chains. Here we demonstrate evidence that TCR α initiated by rearranging 3′ Vα segment 5′ Jα both chromosomes. Rearrangement then...

Abstract During lymphocyte Ag receptor gene assembly, DNA cleavage by the Rag proteins generates pairs of coding and signal ends that are normally joined into joints joints, respectively, classical nonhomologous end-joining (NHEJ) pathway double strand break repair. Coding can also be aberrantly to each other, generating hybrid through NHEJ or NHEJ-independent pathways, such as Rag-mediated transposition. Hybrid do not participate in formation functional genes alter configuration loci ways...

Immune responses are critically regulated by the functions of CD4 helper T cells. Based on their secreted cytokines, cells further categorized into different subsets like Treg or Th17 cells, which suppress promote inflammatory responses, respectively. Signals from IL-2 activate transcription factor STAT5 to but cell differentiation. Our previous results found that deficiency a dual-specificity phosphatase, DUSP4, induced hyper-activation, enhanced signaling, and increased proliferation. In...

Abstract The third complementarity‐determining region (CDR) of the TCR α and β chains forms loops that engage amino acid residues peptides complexed with MHC. This interaction is central to specific discrimination antigenic‐peptide–MHC complexes by TCR. TCRβ chain CDR3 loop encoded Dβ gene segment flanking portions Vβ Jβ segments. joining these segments imprecise, leading significant variability in length composition. In marked contrast other pairing antigen‐receptor chains, size...

To become mature αβ T cells, developing thymocytes must first assemble a cell receptor (TCR) β chain gene encoding TCRβ that forms pre-TCR. These cells then need to generate TCRα chain, which, when paired with the selectable TCR. Newly generated VJα rearrangements do not encode chains capable of forming TCRs can be excised from chromosome and replaced new rearrangements. Such replacement occurs through process revision whereby Vα segment upstream rearrangement is appended downstream Jα...

Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are key RNA viral sensors for triggering antiviral immunity. The underlying mechanisms RLRs to trigger immunity have yet be explored. Here we report the identification of TAPE (TBK1-associated protein in endolysosomes) as a novel regulator RLR pathways. functionally and physically interacts with RIG-I, MDA5, IPS-1 activate IFN-β promoter. knockdown impairs activation induced by but not IPS-1. TAPE-deficient cells defective cytokine...

Abstract Immunization with superantigen in vivo induces transient activation of superantigen-specific T cells, followed by a superantigen-nonresponsive state. In this study, using TCR α knock-in mouse which the α-chain can be replaced endogenous through secondary rearrangement, we show that immunization changes expression on peripheral recombination-activating genes, and generates DNA double-strand breaks at locus. These results suggest viral superantigens are capable inducing revision. Our...

AbstractTranslocations involving the T cell receptor alpha/delta (TCRα/δ) chain locus, which bring oncogenes in proximity of TCRα enhancer, are one hallmark features human malignancies from ataxia telangiectasia (AT) and non-AT patients. These lesions frequently generated by fusion DNA breaks at TCRα/δ locus to a disperse region centromeric immunoglobulin heavy (IgH) locus. Aberrant VDJ joining accounts for associated cleavage, but molecular mechanism that leads generation "oncogene partner"...