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  • ABC transporters B1, C1 and G2 differentially regulate neuroregeneration in mice. 22545122

    ATP-binding cassette (ABC) transporters are essential regulators of organismic homeostasis, and are particularly important in protecting the body from potentially harmful exogenous substances. Recently, an increasing number of in vitro observations have indicated a functional role of ABC transporters in the differentiation and maintenance of stem cells. Therefore, we sought to determine brain-related phenotypic changes in animals lacking the expression of distinct ABC transporters (ABCB1, ABCG2 or ABCC1).Analyzing adult neurogenesis in ABC transporter-deficient animals in vivo and neuronal stem/progenitor cells in vitro resulted in complex findings. In vivo, the differentiation of neuronal progenitors was hindered in ABC transporter-deficient mice (ABCB1(0/0)) as evidenced by lowered numbers of doublecortin(+) (-36%) and calretinin(+) (-37%) cells. In vitro, we confirmed that this finding is not connected to the functional loss of single neural stem/progenitor cells (NSPCs). Furthermore, assessment of activity, exploratory behavior, and anxiety levels revealed behavioral alterations in ABCB1(0/0) and ABCC1(0/0) mice, whereas ABCG2(0/0) mice were mostly unaffected.Our data show that single ABC transporter-deficiency does not necessarily impair neuronal progenitor homeostasis on the single NSPC level, as suggested by previous studies. However, loss of distinct ABC transporters impacts global brain homeostasis with far ranging consequences, leading to impaired neurogenic functions in vivo and even to distinct behavioral phenotypes. In addition to the known role of ABC transporters in proteopathies such as Parkinson's disease and Alzheimer's disease, our data highlight the importance of understanding the general function of ABC transporters for the brain's homeostasis and the regeneration potential.
    Document Type:
    Reference
    Product Catalog Number:
    MAB377
    Product Catalog Name:
    Anti-NeuN Antibody, clone A60
  • Glutamate transporters EAAT4 and EAAT5 are expressed in vestibular hair cells and calyx endings. 23049999

    Glutamate is the neurotransmitter released from hair cells. Its clearance from the synaptic cleft can shape neurotransmission and prevent excitotoxicity. This may be particularly important in the inner ear and in other sensory organs where there is a continually high rate of neurotransmitter release. In the case of most cochlear and type II vestibular hair cells, clearance involves the diffusion of glutamate to supporting cells, where it is taken up by EAAT1 (GLAST), a glutamate transporter. A similar mechanism cannot work in vestibular type I hair cells as the presence of calyx endings separates supporting cells from hair-cell synapses. Because of this arrangement, it has been conjectured that a glutamate transporter must be present in the type I hair cell, the calyx ending, or both. Using whole-cell patch-clamp recordings, we demonstrate that a glutamate-activated anion current, attributable to a high-affinity glutamate transporter and blocked by DL-TBOA, is expressed in type I, but not in type II hair cells. Molecular investigations reveal that EAAT4 and EAAT5, two glutamate transporters that could underlie the anion current, are expressed in both type I and type II hair cells and in calyx endings. EAAT4 has been thought to be expressed almost exclusively in the cerebellum and EAAT5 in the retina. Our results show that these two transporters have a wider distribution in mice. This is the first demonstration of the presence of transporters in hair cells and provides one of the few examples of EAATs in presynaptic elements.
    Document Type:
    Reference
    Product Catalog Number:
    AQ132P
    Product Catalog Name:
    Goat Anti-Rabbit IgG Antibody, F(ab')2, HRP conjugate
  • Monocarboxylate transporters, blood lactate removal after supramaximal exercise, and fatigue indexes in humans. 15531559

    The present study investigated whether muscular monocarboxylate transporter (MCT) 1 and 4 contents are related to the blood lactate removal after supramaximal exercise, fatigue indexes measured during different supramaximal exercises, and muscle oxidative parameters in 15 humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (gamma(2)), which denoted the blood lactate removal ability. Fatigue indexes were calculated during 1-min all-out (FI(AO)) and repeated 10-s (FI(Sprint)) cycling sprints. Biopsies were taken from the vastus lateralis muscle. MCT1 and MCT4 contents were quantified by Western blots, and maximal muscle oxidative capacity (V(max)) was evaluated with pyruvate + malate and glutamate + malate as substrates. The results showed that the blood lactate removal ability (i.e., gamma(2)) after a 1-min all-out test was significantly related to MCT1 content (r = 0.70, P less than 0.01) but not to MCT4 (r = 0.50, P greater than 0.05). However, greater MCT1 and MCT4 contents were negatively related with a reduction of blood lactate concentration at the end of 1-min all-out exercise (r = -0.56, and r = -0.61, P less than 0.05, respectively). Among skeletal muscle oxidative indexes, we only found a relationship between MCT1 and glutamate + malate V(max) (r = 0.63, P less than 0.05). Furthermore, MCT1 content, but not MCT4, was inversely related to FI(AO) (r = -0.54, P less than 0.05) and FI(Sprint) (r = -0.58, P less than 0.05). We concluded that skeletal muscle MCT1 expression was associated with the velocity constant of net blood lactate removal after a 1-min all-out test and with the fatigue indexes. It is proposed that MCT1 expression may be important for blood lactate removal after supramaximal exercise based on the existence of lactate shuttles and, in turn, in favor of a better tolerance to muscle fatigue.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Dysregulation of dopamine transporters via dopamine D2 autoreceptors triggers anomalous dopamine efflux associated with attention-deficit hyperactivity disorder. 20427663

    The neurotransmitter dopamine (DA) modulates brain circuits involved in attention, reward, and motor activity. Synaptic DA homeostasis is primarily controlled via two presynaptic regulatory mechanisms, DA D(2) receptor (D(2)R)-mediated inhibition of DA synthesis and release, and DA transporter (DAT)-mediated DA clearance. D(2)Rs can physically associate with DAT and regulate DAT function, linking DA release and reuptake to a common mechanism. We have established that the attention-deficit hyperactivity disorder-associated human DAT coding variant Ala559Val (hDAT A559V) results in anomalous DA efflux (ADE) similar to that caused by amphetamine-like psychostimulants. Here, we show that tonic activation of D(2)R provides support for hDAT A559V-mediated ADE. We determine in hDAT A559V a pertussis toxin-sensitive, CaMKII-dependent phosphorylation mechanism that supports D(2)R-driven DA efflux. These studies identify a signaling network downstream of D(2)R activation, normally constraining DA action at synapses, that may be altered by DAT mutation to impact risk for DA-related disorders.
    Document Type:
    Reference
    Product Catalog Number:
    MAB369
    Product Catalog Name:
    Anti-Dopamine Transporter Antibody, NT, clone DAT-Nt
  • Vesicular glutamate transporters define two sets of glutamatergic afferents to the somatosensory thalamus and two thalamocortical projections in the mouse. 18181146

    The ventral posterior nucleus of the thalamus (VP) receives two major sets of excitatory inputs, one from the ascending somatosensory pathways originating in the dorsal horn, dorsal column nuclei, and trigeminal nuclei, and the other originating from the cerebral cortex. Both systems use glutamate as neurotransmitter, as do the thalamocortical axons relaying somatosensory information from the VP to the primary somatosensory cortex (SI). The synapses formed by these projection systems differ anatomically, physiologically, and in their capacity for short-term synaptic plasticity. Glutamate uptake into synaptic vesicles and its release at central synapses depend on two isoforms of vesicular glutamate transporters, VGluT1 and VGluT2. Despite ample evidence of their complementary distribution, some instances exist of co-localization in the same brain areas or at the same synapses. In the thalamus, the two transcripts coexist in cells of the VP and other nuclei but not in the posterior or intralaminar nuclei. We show that the two isoforms are completely segregated at VP synapses, despite their widespread expression throughout the dorsal and ventral thalamus. We present immunocytochemical, ultrastructural, gene expression, and connectional evidence that VGluT1 in the VP is only found at corticothalamic synapses, whereas VGluT2 is only found at terminals made by axons originating in the spinal cord and brainstem. By contrast, the two VGluT isoforms are co-localized in thalamocortical axon terminals targeting layer IV, but not in those targeting layer I, suggesting the presence of two distinct projection systems related to the core/matrix pattern of organization of thalamocortical connectivity described in other mammals.
    Document Type:
    Reference
    Product Catalog Number:
    MAB328
    Product Catalog Name:
    Anti-Oligodendrocytes Antibody, clone CE-1
  • SLC7 amino acid transporters of the yellow fever mosquito Aedes aegypti and their role in fat body TOR signaling and reproduction. 22266018

    An important function of the fat body in adult female mosquitoes is the conversion of blood meal derived amino acids (AA) into massive amounts of yolk protein precursors. A highly efficient transport mechanism for AAs across the plasma membrane of the fat body trophocytes is essential in order to deliver building blocks for the rapid synthesis of large amounts of these proteins. This mechanism consists in part of AA transporter proteins from the solute carrier family. These transporters have dual function; they function as transporters and participate in the nutrient signal transduction pathway that is activated in the fat body after a blood meal. In this study we focused on the solute carrier 7 family (SLC7), a family of AA transporters present in all metazoans that includes members with strong substrate specificity for cationic AAs.We identified 11 putative SLC7 transporters in the genome sequence of Aedes aegypti. Phylogenetic analysis puts five of these in the cationic AA transporter subfamily (CAT) and six in the heterodimeric AA transporter (HAT) subfamily. All 11 A. aegypti SLC7 genes are expressed in adult females. Expression profiles are dynamic after a blood meal. We knocked down six fat body-expressed SLC7 transporters using RNAi and found that these 'knockdowns' reduced AA-induced TOR signaling. We also determined the effect these knockdowns had on the number of eggs deposited following a blood meal.Our analysis stresses the importance of SLC7 transporters in TOR signaling pathway and mosquito reproduction.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • High-affinity transporters for NAD+ precursors in Candida glabrata are regulated by Hst1 and induced in response to niacin limitation. 19451228

    The yeast Candida glabrata is an opportunistic pathogen of humans. C. glabrata is a NAD(+) auxotroph, and its growth depends on the availability of niacin (environmental vitamin precursors of NAD(+)). We have previously shown that a virulence-associated adhesin, encoded by EPA6, is transcriptionally induced in response to niacin limitation. Here we used transcript profiling to characterize the transcriptional response to niacin limitation and the roles of the sirtuins Hst1, Hst2, and Sir2 in mediating this response. The majority of genes transcriptionally induced by niacin limitation are regulated by Hst1, suggesting that it is the primary sensor of niacin limitation in C. glabrata. We show that three highly induced genes, TNA1, TNR1, and TNR2, encode transporters which are necessary and sufficient for high-affinity uptake of NAD(+) precursors. Strikingly, if a tna1 tnr1 tnr2 mutant is starved for niacin, it exhibits an extended lag phase, suggesting a central role for the transporters in restoring NAD(+) homeostasis after niacin limitation. Lastly, we had previously shown that the adhesin encoded by EPA6 is induced during experimental urinary tract infection (UTI); we show here that EPA6 transcriptional induction during UTI is strongly enhanced in the tna1 tnr1 tnr2 mutant strain, implicating the transporters in the growth of C. glabrata during infection.
    Document Type:
    Reference
    Product Catalog Number:
    17-320
    Product Catalog Name:
    Histone Deacetylase Assay Kit (HDAC)
  • Monocarboxylate transporters 1 and 4 are associated with CD147 in cervical carcinoma. 19597291

    Due to the highly glycolytic metabolism of solid tumours, there is an increased acid production, however, cells are able to maintain physiological pH through plasma membrane efflux of the accumulating protons. Acid efflux through MCTs (monocarboxylate transporters) constitutes one of the most important mechanisms involved in tumour intracellular pH maintenance. Still, the molecular mechanisms underlying the regulation of these proteins are not fully understood. We aimed to evaluate the association between CD147 (MCT1 and MCT4 chaperone) and MCT expression in cervical cancer lesions and the clinico-pathological significance of CD147 expression, alone and in combination with MCTs. The series included 83 biopsy samples of precursor lesions and surgical specimens of 126 invasive carcinomas. Analysis of CD147 expression was performed by immunohistochemistry. CD147 expression was higher in squamous and adenocarcinoma tissues than in the non-neoplastic counterparts and, importantly, both MCT1 and MCT4 were more frequently expressed in CD147 positive cases. Additionally, co-expression of CD147 with MCT1 was associated with lymph-node and/or distant metastases in adenocarcinomas. Our results show a close association between CD147 and MCT1 and MCT4 expressions in human cervical cancer and provided evidence for a prognostic value of CD147 and MCT1 co-expression.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Age-related changes in dopamine transporters and accumulation of 3-nitrotyrosine in rhesus monkey midbrain dopamine neurons: relevance in selective neuronal vulnerability ... 18598263

    Aging is the strongest risk factor for developing Parkinson's disease (PD). There is a preferential loss of dopamine (DA) neurons in the ventral tier of the substantia nigra (vtSN) compared to the dorsal tier and ventral tegmental area (VTA) in PD. Examining age-related and region-specific differences in DA neurons represents a means of identifying factors potentially involved in vulnerability or resistance to degeneration. Nitrative stress is among the factors potentially underlying DA neuron degeneration. We studied the relationship between 3-nitrotyrosine (3NT; a marker of nitrative damage) and DA transporters [DA transporter (DAT) and vesicular monoamine transporter-2 (VMAT)] during aging in DA subregions of rhesus monkeys. The percentage of DA neurons containing 3NT increased significantly only in the vtSN with advancing age, and the vtSN had a greater percentage of 3NT-positive neurons when compared to the VTA. The relationship between 3NT and DA transporters was determined by measuring fluorescence intensity of 3NT, DAT and VMAT staining. 3NT intensity increased with advancing age in the vtSN. Increased DAT, VMAT and DAT/VMAT ratios were associated with increased 3NT in individual DA neurons. These results suggest nitrative damage accumulates in midbrain DA neurons with advancing age, an effect exacerbated in the vulnerable vtSN. The capacity of a DA neuron to accumulate more cytosolic DA, as inferred from DA transporter expression, is related to accumulation of nitrative damage. These findings are consistent with a role for aging-related accrual of nitrative damage in the selective vulnerability of vtSN neurons to degeneration in PD.
    Document Type:
    Reference
    Product Catalog Number:
    MAB369
    Product Catalog Name:
    Anti-Dopamine Transporter Antibody, NT, clone DAT-Nt