shown that changes in NMDA receptor binding do not coincide with changes in NR1 subunitexpression across regions of the rat and human brain 13 , and across conditions in the pre-frontal cortex of Parkinsonian patients compared to controls 12 . Differences between in vivo glutamate receptor binding and single subunitexpression data may be a result of ligand binding that changes with expression and receptor assembly of not one but multiple different subunits. Using in vitro glutamate receptor expression systems, Laurie et al. 11 have shown that multiple different NMDA subunits (e.g. NR2A, NR2B, NR2C, NR2D) can alter receptor binding.
goes down (Fig. 5). Concomitantly, miR-19a decreases as GluN2A reaches its mature level. REST targeting by miR-539 may smoothly implement the transition by dir- ectly or indirectly coordinating the developmental re- duction of both Grin2b and REST. These transitions require an extensively parameterized network of control elements capable of operating as a closed-loop system from the time of induction until a new equilibrium is reached. miRNAs act in small-scale gene regulatory net- works with defined topologies [25, 26]. These network motifs function in recurrent regulatory circuits, often with transcription factors  and, in this case, imple- ment transitions in the NMDAR subunit composition.
N-methyl-D-aspartate (NMDA) receptors are mainly involved in opioid addiction and are highly expressed in the brain reward pathway. Presence of GluN3A subunit in the composition of NMDA receptor decreases conductance of receptor channel. Opioid administration may change the expression pattern of NMDA receptor subunits. Here we have investigated the mRNA expression alterations of GluN3A subunit of the NMDA receptor in the rat brain after acute and chronic morphine administration. Male Wistar rats received chronic intraperitoneal injections of escalating doses of morphine twice daily for 6 days. Control animals received saline instead of morphine with the same protocol. Two other groups received acute single dose of morphine (30 mg/kg) or saline, respectively. The mRNA expression of GluN3A subunit of NMDA receptor in prefrontal cortex, hippocampus, striatum, and nucleus accumbens was evaluated using real-time PCR method. The mRNA expression level of GluN3A subunit was significantly increased (1.5 fold) in prefrontal cortex in chronic morphine administered rats compared to control group. No statistically significant difference was observed between control and chronic morphine treated rats in other sites of the brain. In acute morphine administered animals, no significant difference was observed in GluN3A subunitexpression in evaluated sites of the brain compared to the control group. It is concluded that chronic morphine administration leads to the up-regulation of GluN3A subunit of NMDA receptor in prefrontal cortex. Involvement of this alteration in features of opioid addiction needs to be further studies in the future.
associated reduction in proteasome activity confirms and extends previous studies by demonstrating this phenomenon in the human brain and suggests that reduced subunitexpression may directly lead to proteasome impairment. The reason for the reduction in RPT6 ATPase subunitexpression remains unexplained. It is possible that the reduction could be related to oxidative stress; indeed, proteasome subunits were demonstrated to be sensitive to oxidative stress [39, 40]. Furthermore, Sun et al. reported that proteasome subunits (RPT5, Rpn10 and Rpn2) can be cleaved by caspase-3 following caspase activation during apoptosis; they found decreased proteasome activity to be associated with the cleavage of these subunits .
parities between the effects of endog- enous GCs and of exogenous GCs may inﬂuence results for the association of ENaC subunitexpression with GCs. In particular, the biological potency of dexamethasone is considerably higher than that of cortisol. This may, besides differential mode and dose of expo- sure, account for the fact that in an earlier, limited preterm population with bronchopulmonary dysplasia, postnatal parenteral administration of dexamethasone induced both ␣ -ENaC and ␤ -ENaC. 18
As previously discussed epilepsy is associated with severe comorbidities and recent literature has suggested that KARs and alteration in subunitexpression may be implicated. We suggest that the apparent downregulation of KAR subunitexpression and KAR-mediated transmission within area CA3, while likely a compensatory modification, may be associated with noted comorbidities. As previously elaborated upon, the reduction in KAR function may be a compensatory mechanism to limit excitability. However the trade-off may be the occurrence of comorbidities, particularly those linked to the mossy fiber – CA3 pathway. While controversy surrounds mossy fiber induced LTP (Henze et al., 2000), it is apparent that the mossy fiber – CA3 synapse demonstrates the ability to undergo long-term or even permanent alterations. The observed decrease in KAR function at this synapse may likely contribute to cognitive impairment, specifically associated with memories. The process of encoding and retrieving memories has been associated with gamma frequencies, ~30 – 80 Hz (Herrmann et al., 2004; Bartos et al., 2007). In the current study we observed a selective reduction in the area of the fEPSP KA at frequencies of 30 – 100Hz, those similar
Fig. 2. Visualisation of maternal gene product spatial distribution in uncleaved zygotes of Lymnaea stagnalis by whole mount in situ hybridisation. Eight maternal gene products were visualised in uncleaved zygotes relative to a negative control (b-tubulin). (A) b-tubulin is not detectable in uncleaved zygotes. A polar body is indicated by the horizontal arrow. (B) b-tubulin is clearly expressed in ciliated cells of older veliger larvae. (C) contig_2724: ATP-dependent RNA helicase dhx8. (D) contig_453: heat shock 70 kda protein cognate 4. (E) contig_7974: ADP-ribosylation factor 4. (F) contig_9053: proteasome alpha 6 subunit. (G) contig_579: ergic and golgi 2. (H) contig_9016: eukaryotic translation initiation factor 3 subunit i. (I) contig_8075: eukaryotic translation elongation factor. (J) contig_8318: 78 kda glucose-regulated protein. stagnalis genes had putative orthologues in all seven taxa (Supplementary Table 1). These 481 orthologues in fact probably represent 439 or fewer distinct genes, as BLASTx analyses revealed that some matched the same sequence in the NCBI nr protein database. This result implies that 5-10% of the maternal transcriptome is conserved and shared across all of the representa- tive taxa (H. sapiens 6.1%, M. musculus 9.9%, D. rerio 10.6%, C. intestinalis 11.4%, D. melanogaster 7.0%, C. elegans 9.0%). We refer to this conserved set as the “conserved maternal transcriptome” (COMAT).
available at stable quality and protein engineering studies are possible for the first time. The purification using the N-terminal His-tag via nickel based affinity chromatography turned out to be efficient and fast. While in previous purifications of the enzyme from wild type cultivations, huge culture volumes were used, in this study drastically smaller amounts of heterolo- gous culture is needed to produce comparable amounts of pure protein. Conrad et al. used a 10 L culture and obtained 240 mL crude extract to produce 52 mg of pure protein via a chromatography based purification protocol with three steps, which corre- sponds to a recovery of 15% (Conrad et al. 1965a,). 28 years later Jones et al. were able to increase the purity and the yield up to 19.5%. From a 10 L culture volume 49 mg of pure enzyme were obtained (Jones et al. 1993). In this work 8 mg of pure protein were achieved out of a 400 mL culture, which highlights the advan- tages of recombinant expression and the fusion of an enzyme to a His-tag.
Our finding that VPS35, a key component of the retromer complex, is a binding partner of SorCS2 is consistent with the literature that the retromer complex binds directly to other VPS10P family members sortilin and SorLA (73–75), utilizing aromatic motifs in the cytoplasmic tail of VPS10P sorting receptors (76). The retromer complex is emerging as a major regulator of endosomal sorting (77) and maintains sur- face expression of membrane proteins by retrieving cargo for recycling (78, 79) as well as preventing their lysosomal degradation (80). Importantly, it has been shown that retromer also interacts with HTT protein (35) and regulates local NMDAR recycling in dendrites (36). Loss of retromer activity can cause dimin- ished NMDA currents (36), progressive synaptic dysfunction, and neuronal degeneration (81), which are reminiscent of the phenotypes reported in HD mouse models (31, 50, 55).
The first knock-out of V-ATPase in an animal was obtained from Drosophila melanogaster. A fly mutant with lethal P- element insertions in the vha55 gene for the B subunit was identified by Davies et al. (1996). Deletion of the B subunit locus was shown to be lethal, whereas point mutations gave varying phenotypes that ranged from lethal to surviving flies. These results suggest that V-ATPase in organelles or plasma membranes is essential for the development from larva to fly. The same question can be asked regarding mammalian V- ATPase. The mouse subunit c gene (PL16) is an appropriate target to knock out because no isoforms have been found. Chromosomal PL16 was replaced by the neomycin-resistance gene using target-directed mutagenesis (Inoue et al., 2000). No PL16 −/− mouse has been identified at birth, while PL16 +/− embryos were viable and showed no noticeable abnormality. These results indicate that the homozygous loss of the c subunit gene caused embryonic lethality. However, the PL16 −/− embryo could develop into the blastocyst stage in vitro (G. H. Sun-Wada, Y. Wada and M. Futai, in preparation). Furthermore, the mutant blastocysts formed acidic compartments similar to those of the wild type, suggesting that the maternal mRNA is sufficient for establishing an acidic compartment up to the blastocyst stage. Embryos of the same stage were also detected in vivo, but none was attached to the uterine epithelium after 7 days post coitus. These results suggest that V-ATPase or acidic organelles are essential immediately before gastrulation in mammals.
Figure 5 gemcitabine enhanced carboplatin-induced Dna damage and apoptosis in cervical cancer cells. (A) siha cells were treated with gemcitabine or/and carboplatin for 6 hours. Immunofluorescence analysis was used to detect γ-h2aX expression. (B) The quantitative data from Figure 5a and γ-h2aX-positive cells were calculated as Figure 3c (*P,0.05). (C) siha cells were treated with the indicated drugs for 6 hours. γ-h2aX protein expression was analyzed by Western blotting. (D) siha cells were treated with the drugs indicated for 72 hours. Apoptosis was analyzed by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining assay. (E) The degree of apoptotic cell death was quantified for each condition. Data represented the mean ± standard deviation of three individual experiments (*P,0.05).
Following his time in Yale and as a University Demonstrator, Richard was appointed to a Lectureship in the Department of Biochemistry in Cambridge in 1969. There he developed a number of important techniques in protein chemistry, including reversible citraconylation of amino groups (3), amidination of lysine residues (23, 28), hybridization of native and chemically modified subunits in oligomeric enzymes to study subunit interactions (12), and reversible chemical cross-linking to probe the quaternary structure of protein complexes (14, 27). These methods were widely used in the 1970s to interrogate protein structure and function, until the development of site-directed mutagenesis in the 1980s which rapidly replaced the ‘old-fashioned’ and much less specific methods of chemical modification. Ironically, following the advent of mass spectrometry for protein sequencing (Wilm et al, 1996; Abersold & Mann, 2003; Taouatas et al, 2008) these ‘old-fashioned’ methods are enjoying a resurgence of popularity, with researchers worldwide needing to re-discover the tricks of chemical modification developed by Richard and his colleagues more than 40 years ago (3, 5, 6, 8, 11, 14, 28).
neuron shifts towards that of the given stimuli (Schuett et al., 2001). Reversing the pairing order (so that the neuron fires before the visual stimuli) weakens the orientation preference away from the given orientation in a tLTD-like manner. Additionally, the pairing of visual stimuli at two orientations shifts the orientation preference of V1 neurons depending on the temporal order of the pairings and can be predicted based on the temporal windows of STDP induced in vitro (H. Yao & Dan, 2001). The ability to modify visual responses via STDP learning rules exists through adulthood, as the pairing of visual stimuli can rapidly modify receptive fields and orientation preferences in adult cats (Fu et al., 2002; H. Yao & Dan, 2001). Lastly, STDP learning rules have been shown to be sufficient to segregate sensory inputs onto specific dendritic branches, underscoring how STDP may be essential for shaping cortical connectivity (Froemke et al., 2005). Overall these observations suggest that STDP provides a powerful mechanism by which visual cortical circuitry can be modeled and by which neurons can rapidly adapt to an ever-changing visual environment throughout life. Many synaptic proteins implicated in STDP induction or expression are
Diabetic neuropathy is associated with profound loss of distal limb sensation and/or pain, causing significant decline in the quality of life and potential morbidity and mortality for patients. Currently, there are no clin- ical treatments that successfully improve neuropathic damage to peripheral sensory nerve fibers, likely due to the multifactorial etiology of neuropathy development and progression. Here, we have demonstrated in vivo PNS insulin resistance in ob/ob mice. These results are consistent with recent in vitro studies and support the view that altered insulin signaling may contribute to DN . A robust activation of insulin-sensitive path- ways was observed in the DRG and sciatic nerve of nondiabetic mice, with a blunted response in both tis- sues from insulin-resistant ob/ob mice. While no one mechanism of insulin resistance was clearly prevalent, significant changes were seen in two known pathways of insulin resistance, including increased JNK activity and reduced insulin receptor expression. Although more research is needed to fully elucidate the path- ways leading to PNS insulin resistance, these results suggest that cellular mechanisms of insulin resistance that have been defined in muscle may also play an im- portant role in the PNS.
The transmembrane isoform of Fc gamma RIII, Fc gamma RIIIA, is found on NK cells, cultured monocytes, and tissue macrophages in association with a dimer of an accessory subunit, either gamma or zeta. Functions of individual Fc receptors have been difficult to analyze due to coexpression of the receptors on hematopoietic cells and permanent cell lines expressing Fc receptors. cDNAs for the alpha and gamma subunits of Fc gamma RIIIA were cotransfected into COS-1 cells, which lack endogenous Fc receptors, to evaluate receptor-mediated phagocytosis and changes in [Ca2+]i. Transfectants both bound and phagocytosed IgG-sensitized erythrocytes and, following activation of Fc gamma RIIIA, increased [Ca2+]i. The gamma subunit was essential both for the surface expression of the receptor and for transduction of the phagocytic signal. Truncation of the gamma subunit cytoplasmic domain (amino acids 65-80) eliminated phagocytic function. Phorbol ester inhibited phagocytosis in a concentration-dependent manner, but did not affect IgG- sensitized erythrocytes binding, suggesting that a protein kinase C-dependent pathway inhibits phagocytosis. The data indicate that a tyrosine containing cytoplasmic domain within the gamma subunit is required for phagocytosis by Fc gamma RIIIA.
receptors), while stromal cells expressed predominantly alpha 5 (fibronectin receptor). The presence of alpha 1 on glandular epithelial cells was cycle specific, found only during the secretory phase. Expression of both subunits of the vitronectin receptor, alpha v beta 3, also underwent cycle specific changes on endometrial epithelial cells. Immunostaining for alpha v increased throughout the menstrual cycle, while the beta 3 subunit appeared abruptly on cycle day 20 on luminal as well as glandular epithelial cells. Discordant luteal phase biopsies (greater than or equal to 3 d "out of phase") from infertility patients exhibited
p53 primarily acts as a sequence-specific transcription factor. However, there are several examples showing that p53 can enhance transcription that is mediated by other transcription factors from their respective nearby binding sites. Recently, Lion et al. discovered that the combined activation of p53 and estrogen receptor α pathways induce expression of a unique set of genes beyond those induced by activation of only p53 or estrogen receptor . Bisio et al have shown that combination of p53 and TNFα receptor activation resulted in synergistic gene expression . Choy et al demonstrated that mir-21 expression depends on formation of p53/NFκB/STAT3 complex at NFκB response elements (REs) at the mir-21 promoter. In addition, several histone modifying enzymes including histone methyltransferases (PRMT1 and CARM1) and histone acetyltransferases (p300/CBP, pCAF, GCN5 and TIP60) are recruited to DNA in a p53-dependent fashion in the vicinity of p53 REs and thereby facilitate formation of pre-initiation complex and RNAPII-dependent transcription (see  for review). Our analysis shows that p53 can potentially bind at promoter areas of many Synergistic Targets. Therefore, one possible mechanism by which p53 can enhance transcription of these genes could involve p53 assisting in the recruitment of transcriptional machinery to these promoters, thereby priming them for increased transcription.
nAChR expression can be achieved using different RIC-3-to- receptor ratios, and that sensitivity of nAChR maturation to this ratio depends on the identity of the nAChR and on the specific RIC-3 isoform (different isoforms are produced by alternative splicing, see below) 31 . Second, RIC-3 was shown
transcriptional factors [5, 6]. The Mediator complex has frequently been described to be differentially expressed or mutated in diverse tumor entities . Interestingly, MED15 belongs to the tail module of the Mediator com- plex, which is known to receive and integrate information from diverse signaling pathways such as the transforming growth factor-β (TGF-β) and sterol regulatory element- binding protein (SREBP) pathways [8–10]. While some cancer entities were shown to be strongly associated with MED deregulation, knowledge about the Mediator com- plex expression profile in TGCT has been lacking so far.