Millipore Sigma Vibrant Logo
 

5++m


550 Results Búsqueda avanzada  
Mostrar
Productos (70)
Documentos (355)
Páginas (125)

Acote sus resultados Utilice los filtros siguientes para refinar su búsqueda

Tipo de documento

  • (349)
  • (3)
  • (3)
¿No encuentra lo que está buscando?
Póngase en contacto con
el Servicio de Atención
al Cliente

 
¿Necesita ayuda para encontrar un documento?

  • Skeletal dysplasias due to filamin A mutations result from a gain-of-function mechanism distinct from allelic neurological disorders. 19773341

    Filamin A (FLNA) crosslinks F-actin and binds proteins consistent with roles integrating cell signalling and the cytoskeleton. FLNA missense mutations are associated with the otopalatodigital syndrome (OPD) spectrum of skeletal disorders, clustering in discrete domains. One cluster is found in the second calponin homology domain of the FLNA actin-binding domain (ABD), implicating this region as essential for mediating correct function. Here we show that OPD (FLNA E254K) fibroblast lysates have equivalent concentrations of FLNA compared with controls and that recombinant FLNA E254K ABD has increased in vitro F-actin binding (K(d) 13 microm) compared with wild type (WT; K(d) 48 microm). These observations are consistent with a gain-of-function mechanism for OPD. We have determined the crystal structures of the WT and E254K FLNA ABDs at 2.3 A resolution, revealing that they adopt similar closed conformations. The E254K mutation removes a conserved salt bridge but does not disrupt the ABD structure. The solution structures are also equivalent as determined by circular dichroism spectroscopy, but differential scanning fluorimetry denaturation showed reduced stability (decreased T(m) of 5.6 degrees C) for E254K relative to WT. Ex vivo characterization of E254K OPD patient fibroblasts revealed they have similar motility and adhesion as control cells, implying that many core functions mediated by FLNA are unaffected, consistent with OPD only affecting specific tissues despite FLNA being widely expressed. These data provide the first biochemical evidence for a gain-of-function mechanism for the OPD disorders, and mechanistically distinguishes them from the loss-of-function phenotypes that manifest as disorders of neuronal migration.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1678
    Nombre del producto:
    Anti-Filamin A Antibody, clone PM6/317

  • p68 RNA helicase is an essential human splicing factor that acts at the U1 snRNA-5' splice site duplex. 12101238

    Modulation of the interaction between U1 snRNP and the 5' splice site (5'ss) is a key event that governs 5'ss recognition and spliceosome assembly. Using the methylene blue-mediated cross-linking method (Z. R. Liu, A. M. Wilkie, M. J. Clemens, and C. W. Smith, RNA 2:611-621, 1996), a 65-kDa protein (p65) was shown to interact with the U1-5'ss duplex during spliceosome assembly (Z. R. Liu, B. Sargueil, and C. W. Smith, Mol. Cell. Biol. 18:6910-6920, 1998). In this report, p65 was identified as p68 RNA helicase and shown to be essential for in vitro pre-mRNA splicing. Depletion of endogenous p68 RNA helicase does not affect the loading of the U1 snRNP to the 5'ss during early stage of splicing. However, dissociation of the U1 from the 5'ss is largely inhibited. The data suggest that p68 RNA helicase functions in destabilizing the U1-5'ss interactions. Furthermore, depletion of p68 RNA helicase arrested spliceosome assembly at the prespliceosome stage, suggesting that p68 may play a role in the transition from prespliceosome to spliceosome.
    Tipo de documento:
    Referencia
    Referencia del producto:
    05-850
    Nombre del producto:
    Anti-p68 Antibody, clone204

  • The amino-terminal tails of the core histones and the translational position of the TATA box determine TBP/TFIIA association with nucleosomal DNA. 8524642

    We establish that the TATA binding protein (TBP) in the presence of TFIIA recognizes the TATA box in nucleosomal DNA dependent on the dissociation of the amino-terminal tails of the core histones from the nucleosome and the position of the TATA box within the nucleosome. We examine TBP/TFIIA access to the TATA box with this sequence placed in four distinct rotational frames with reference to the histone surface and at three distinct translational positions at the edge, side and dyad axis of the nucleosome. Under our experimental conditions, we find that the preferential translational position at which TBP/TFIIA can bind the TATA box is within linker DNA at the edge of the nucleosome and that binding is facilitated if contacts made by the amino-terminal tails of the histones with nucleosomal DNA are eliminated. TBP/TFIIA binding to DNA at the edge of the nucleosome occurs with the TATA box in all four rotational positions. This is indicative of TBP/TFIIA association directing the dissociation of the TATA box from the surface of the histone octamer.
    Tipo de documento:
    Referencia
    Referencia del producto:
    20-129

  • Methionine sulfoxide reductase A (MsrA) protects cultured mouse embryonic stem cells from H2O2-mediated oxidative stress. 20506347

    Methionine sulfoxide reductase A (MsrA), a member of the Msr gene family, can reduce methionine sulfoxide residues in proteins formed by oxidation of methionine by reactive oxygen species (ROS). Msr is an important protein repair system which can also function to scavenge ROS. Our studies have confirmed the expression of MsrA in mouse embryonic stem cells (ESCs) in culture conditions. A cytosol-located and mitochondria-enriched expression pattern has been observed in these cells. To confirm the protective function of MsrA in ESCs against oxidative stress, a siRNA approach has been used to knockdown MsrA expression in ES cells which showed less resistance than control cells to hydrogen peroxide treatment. Overexpression of MsrA gene products in ES cells showed improved survivability of these cells to hydrogen peroxide treatment. Our results indicate that MsrA plays an important role in cellular defenses against oxidative stress in ESCs. Msr genes may provide a new target in stem cells to increase their survivability during the therapeutic applications.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Identification of tyrosine hydroxylase as a physiological substrate for Cdk5. 15447670

    Cyclin-dependent kinase 5 (Cdk5) is emerging as a neuronal protein kinase involved in multiple aspects of neurotransmission in both post- and presynaptic compartments. Within the reward/motor circuitry of the basal ganglia, Cdk5 regulates dopamine neurotransmission via phosphorylation of the postsynaptic signal transduction pathway integrator, DARPP-32 (dopamine- and cyclic AMP-regulated phosphoprotein, M(r) 32,000). Cdk5 has also been implicated in regulating various steps in the presynaptic vesicle cycle. Here we report that Cdk5 phosphorylates tyrosine hydroxylase (TH), the key enzyme for synthesis of dopamine. Using phosphopeptide mapping, site-directed mutagenesis, and phosphorylation state-specific antibodies, the site was identified as Ser31, a previously defined extracellular signal-regulated kinases 1/2 (ERK1/2) site. The phosphorylation of Ser31 by Cdk5 versus ERK1/2 was investigated in intact mouse striatal tissue using a pharmacological approach. The results indicated that Cdk5 phosphorylates TH directly and also regulates ERK1/2-dependent phosphorylation of TH through the phosphorylation of mitogen-activated protein kinase kinase 1 (MEK1). Finally, phospho-Ser31 TH levels were increased in dopaminergic neurons of rats trained to chronically self-administer cocaine. These results demonstrate direct and indirect regulation of the phosphorylation state of a Cdk5/ERK1/2 site on TH and suggest a role for these pathways in the neuroadaptive changes associated with chronic cocaine exposure.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB1542
    Nombre del producto:
    Anti-Tyrosine Hydroxylase Antibody

  • Phosphorylation of MEK1 by cdk5/p35 down-regulates the mitogen-activated protein kinase pathway. 11684694

    Cyclin-dependent protein kinase 5 (cdk5), a member of the cdk family, is active mainly in postmitotic cells and plays important roles in neuronal development and migration, neurite outgrowth, and synaptic transmission. In this study we investigated the relationship between cdk5 activity and regulation of the mitogen-activated protein (MAP) kinase pathway. We report that cdk5 phosphorylates the MAP kinase kinase-1 (MEK1) in vivo as well as the Ras-activated MEK1 in vitro. The phosphorylation of MEK1 by cdk5 resulted in inhibition of MEK1 catalytic activity and the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. In p35 (cdk5 activator) -/- mice, which lack appreciable cdk5 activity, we observed an increase in the phosphorylation of NF-M subunit of neurofilament proteins that correlated with an up-regulation of MEK1 and ERK1/2 activity. The activity of a constitutively active MEK1 with threonine 286 mutated to alanine (within a TPXK cdk5 phosphorylation motif in the proline-rich domain) was not affected by cdk5 phosphorylation, suggesting that Thr286 might be the cdk5/p35 phosphorylation-dependent regulatory site. These findings support the hypothesis that cdk5 and the MAP kinase pathway cross-talk in the regulation of neuronal functions. Moreover, these data and the recent studies of Harada et al. (Harada, T., Morooka, T., Ogawa, S., and Nishida, E. (2001) Nat. Cell Biol. 3, 453-459) have prompted us to propose a model for feedback down-regulation of the MAP kinase signal cascade by cdk5 inactivation of MEK1.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-339

  • Regulation of ribosomal protein S6 phosphorylation by casein kinase 1 and protein phosphatase 1. 21233202

    Ribosomal protein S6 (rpS6) is a critical component of the 40 S ribosomal subunit that mediates translation initiation at the 5'-m(7)GpppG cap of mRNA. In response to mitogenic stimuli, rpS6 undergoes ordered C-terminal phosphorylation by p70 S6 kinases and p90 ribosomal S6 kinases on four conserved Ser residues (Ser-235, Ser-236, Ser-240, and Ser-244) whose modification potentiates rpS6 cap binding activity. A fifth site, Ser-247, is also known to be phosphorylated, but its function and regulation are not well characterized. In this study, we employed phospho-specific antibodies to show that Ser-247 is a target of the casein kinase 1 (CK1) family of protein kinases. CK1-dependent phosphorylation of Ser-247 was induced by mitogenic stimuli and required prior phosphorylation of upstream S6 kinase/ribosomal S6 kinase residues. CK1-mediated phosphorylation of Ser-247 also enhanced the phosphorylation of upstream sites, which implies that bidirectional synergy between C-terminal phospho-residues is required to sustain rpS6 phosphorylation. Consistent with this idea, CK1-dependent phosphorylation of rpS6 promotes its association with the mRNA cap-binding complex in vitro. Additionally, we show that protein phosphatase 1 (PP1) antagonizes rpS6 C terminus phosphorylation and cap binding in intact cells. These findings further our understanding of rpS6 phospho-regulation and define a direct link between CK1 and translation initiation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    ABN299

  • Membrane localization of the U2 domain of Protein 4.1B is necessary and sufficient for meningioma growth suppression. 15688033

    Meningiomas are common central nervous system tumors; however, the molecular mechanisms underlying their pathogenesis are largely undefined. Previous work has implicated Protein 4.1B as an important tumor suppressor involved in the development of these neoplasms. In this report, we demonstrate that the U2 domain is necessary and sufficient for the ability of Protein 4.1B to function as a meningioma growth suppressor. Using a series of truncation and deletion constructs of DAL-1 (a fragment of Protein 4.1B that retains all the growth suppressive properties), we narrowed the domain required for 4.1B growth suppression to a fragment containing a portion of the FERM domain and the U2 domain using clonogenic assays on meningioma cells. Deletion of the U2 domain in the context of the full-length DAL-1 molecule eliminated growth suppressor function, as measured by thymidine incorporation and caspase-3 activation. Moreover, targeting the U2 domain to the plasma membrane using a membrane localization signal (MLS) reduced cell proliferation, similar to wild-type DAL-1. Collectively, the data suggest that the U2 domain, when properly targeted to the plasma membrane, contains all the residues necessary for mediating Protein 4.1B growth suppression.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-503
    Nombre del producto:
    Anti-Caspase 1 Antibody

  • Transplantation of olfactory mucosa following spinal cord injury promotes recovery in rats. 18695502

    Several recent studies have demonstrated the potential therapeutic role of olfactory ensheathing cells in spinal cord injury. The aim of this study was to elucidate whether grafts of nasal olfactory mucosa containing olfactory ensheathing cells can repair the injured rat spinal cord as compared with the nasal respiratory mucosa containing no olfactory ensheathing cells. These grafts were then transplanted into the partially removed rat spinal cord. Compared with the respiratory mucosa-transplanted rats, the olfactory mucosa-transplanted rats partially recovered the movement of their hindlimbs and joints. Corticospinal tracing indicated that olfactory mucosa transplantation restored the severed tract. Therefore, olfactory mucosa has potential value in the repair of spinal cord injury.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB365
    Nombre del producto:
    Anti-Nerve Growth Factor Receptor Antibody, extracellular, clone 192-IgG

  • Selection and characterization of recombinant clones that produce Mycobacterium leprae antigens recognized by antibodies in sera from household contacts of leprosy patien ... 1696931

    A Mycobacterium leprae expression library was constructed in the vectors EX1, pEX2, and pEX3 and screened with a pool of 19 well-absorbed sera from household contacts of leprosy patients. Twelve selected recombinants that were further characterized differed clearly from recombinants selected with murine monoclonal antibodies. Whereas the monoclonal antibodies recognized mainly six recombinant antigens, the human sera from contacts reacted with a range of different recombinant antigens. None of the contact recombinant antigens was identical or related to well-characterized antigens from M. leprae or other mycobacteria selected with monoclonal antibodies, including proteins of the heat shock families. Two groups of recombinant antigens could be distinguished: one that was recognized by all sera used in the pool and one that was recognized by only a limited number of sera. These antigens, selected with sera from household contacts of previously untreated lepromatous leprosy patients, may be relevant to the immune responses during the early phase of infection with M. leprae.
    Tipo de documento:
    Referencia
    Referencia del producto:
    S1120