Millipore Sigma Vibrant Logo
 

cell-


10797 Results Advanced Search  
Showing
Products (0)
Documents (9,936)
Site Content (861)

Narrow Your Results Use the filters below to refine your search

Document Type

  • (9,176)
  • (414)
  • (109)
  • (103)
  • (45)
  • Show More
Can't Find What You're Looking For?
Contact Customer Service

 

  • Cell 21962515

    Protein tyrosine phosphatase 1B (PTP1B) plays important roles in downregulation of insulin and leptin signaling and is an established therapeutic target for diabetes and obesity. PTP1B is regulated by reactive oxygen species (ROS) produced in response to various stimuli, including insulin. The reversibly oxidized form of the enzyme (PTP1B-OX) is inactive and undergoes profound conformational changes at the active site. We generated conformation-sensor antibodies, in the form of single-chain variable fragments (scFvs), that stabilize PTP1B-OX and thereby inhibit its phosphatase function. Expression of conformation-sensor scFvs as intracellular antibodies (intrabodies) enhanced insulin-induced tyrosyl phosphorylation of the β subunit of the insulin receptor and its substrate IRS-1 and increased insulin-induced phosphorylation of PKB/AKT. Our data suggest that stabilization of the oxidized, inactive form of PTP1B with appropriate therapeutic molecules may offer a paradigm for phosphatase drug development.
    Document Type:
    Reference
    Product Catalog Number:
    MABS456
    Product Catalog Name:
    Anti-PTP1B Antibody (Oxidized), clone scFvs 45

  • Red cell antigens P (globoside) and Luke: identification by monoclonal antibodies defining the murine stage-specific embryonic antigens -3 and -4 (SSEA-3 and SSEA-4). 2874662

    Two globoseries antigens (antigens borne on carbohydrate chains containing globoside), SSEA-3 and SSEA-4, were found on the red cells of the majority of people, but were absent from cells of rare p and Pk individuals which lack globoside. In addition, SSEA-4 was absent from red cells of Luke(-) individuals which nevertheless express the P antigen (globoside) and SSEA-3. The name LKE is proposed for the red cell antigen detected by the Luke serum and by MC813-70, the monoclonal antibody defining SSEA-4. Among the LKE+ individuals, a few showed relatively weak expression of the antigen and were grouped separately as a LKE weak (LKEw) phenotype. Using MC813-70, the frequencies of the 3 phenotypes LKE+, LKEw and LKE- in an English donor population are 0.914, 0.072 and 0.014, respectively.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • The T cell receptor: critical role of the membrane environment in receptor assembly and function. 15771567

    Recent studies have demonstrated that cell membranes provide a unique environment for protein-protein and protein-lipid interactions that are critical for the assembly and function of the T cell receptor (TCR)-CD3 complex. Highly specific polar interactions among transmembrane (TM) domains that are uniquely favorable in the lipid environment organize the association of the three signaling dimers with the TCR. Each of these three assembly steps depends on the formation of a three-helix interface between one basic and two acidic residues in the membrane environment. The same polar TM residues that drive assembly also play a central role in quality control and export by directing the retention and degradation of free subunits and partial complexes, while membrane proximal cytoplasmic signals control recycling and degradation of surface receptors. Recent studies also suggest that interactions between the membrane and the cytoplasmic domains of CD3 proteins may be important for receptor triggering.
    Document Type:
    Reference
    Product Catalog Number:
    16-241

  • Host cell detection of noncoding stuffer DNA contained in helper-dependent adenovirus vectors leads to epigenetic repression of transgene expression. 19515759

    Helper-dependent adenovirus (hdAd) vectors have shown great promise as therapeutic gene delivery vehicles in gene therapy applications. However, the level and duration of gene expression from hdAd can differ considerably depending on the nature of the noncoding stuffer DNA contained within the vector. For example, an hdAd containing 22 kb of prokaryotic DNA (hdAd-prok) expresses its transgene 60-fold less efficiently than a similar vector containing eukaryotic DNA (hdAd-euk). Here we have determined the mechanistic basis of this phenomenon. Although neither vector was subjected to CpG methylation and both genomes associated with cellular histones to similar degrees, hdAd-prok chromatin was actively deacetylated. Insertion of an insulator element between the transgene and the bacterial DNA derepressed hdAd-prok, suggesting that foreign DNA nucleates repressive chromatin structures that spread to the transgene. We found that Sp100B/Sp100HMG and Daxx play a role in repressing transgene expression from hdAd and act independently of PML bodies. Thus, we have identified nuclear factors involved in recognizing foreign DNA and have determined the mechanism by which associated genes are repressed.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • T cell activation induces proteasomal degradation of Argonaute and rapid remodeling of the microRNA repertoire. 23382546

    Activation induces extensive changes in the gene expression program of naive CD4(+) T cells, promoting their differentiation into helper T cells that coordinate immune responses. MicroRNAs (miRNAs) play a critical role in this process, and miRNA expression also changes dramatically during T cell differentiation. Quantitative analyses revealed that T cell activation induces global posttranscriptional miRNA down-regulation in vitro and in vivo. Argonaute (Ago) proteins, the core effector proteins of the miRNA-induced silencing complex (miRISC), were also posttranscriptionally down-regulated during T cell activation. Ago2 was inducibly ubiquitinated in activated T cells and its down-regulation was inhibited by the proteasome inhibitor MG132. Therefore, activation-induced miRNA down-regulation likely occurs at the level of miRISC turnover. Measurements of miRNA-processing intermediates uncovered an additional layer of activation-induced, miRNA-specific transcriptional regulation. Thus, transcriptional and posttranscriptional mechanisms cooperate to rapidly reprogram the miRNA repertoire in differentiating T cells. Altering Ago2 expression in T cells revealed that Ago proteins are limiting factors that determine miRNA abundance. Naive T cells with reduced Ago2 and miRNA expression differentiated more readily into cytokine-producing helper T cells, suggesting that activation-induced miRNA down-regulation promotes acquisition of helper T cell effector functions by relaxing the repression of genes that direct T cell differentiation.
    Document Type:
    Reference
    Product Catalog Number:
    MABE900

  • Stem cell factor Sox2 and its close relative Sox3 have differentiation functions in oligodendrocytes. 24257626

    Neural precursor cells of the ventricular zone give rise to all neurons and glia of the central nervous system and rely for maintenance of their precursor characteristics on the closely related SoxB1 transcription factors Sox1, Sox2 and Sox3. We show in mouse spinal cord that, whereas SoxB1 proteins are usually downregulated upon neuronal specification, they continue to be expressed in glial precursors. In the oligodendrocyte lineage, Sox2 and Sox3 remain present into the early phases of terminal differentiation. Surprisingly, their deletion does not alter precursor characteristics but interferes with proper differentiation. Although a direct influence on myelin gene expression may be part of their function, we provide evidence for another mode of action. SoxB1 proteins promote oligodendrocyte differentiation in part by negatively controlling miR145 and thereby preventing this microRNA from inhibiting several pro-differentiation factors. This study presents one of the few cases in which SoxB1 proteins, including the stem cell factor Sox2, are associated with differentiation rather than precursor functions.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • Two cell circuits of oriented adult hippocampal neurons on self-assembled monolayers for use in the study of neuronal communication in a defined system. 23611164

    In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell "bidirectional polarity" circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple