Abnormalities in extracellular glycine and glutamate levels in the striatum of sandy mice

2013 ◽  
Vol 25 (4) ◽  
pp. 215-220
Author(s):  
Yuji Kitaichi ◽  
Ryota Hashimoto ◽  
Takeshi Inoue ◽  
Tomohiro Abekawa ◽  
Aya Kakuta ◽  
...  
Keyword(s):  
Amino Acids ◽  
Candidate Gene ◽  
Glutamate Release ◽  
Glutamatergic Neurotransmission ◽  
Wild Type ◽  
Extracellular Glutamate ◽  
Strong Candidate ◽  
The Relationship ◽  
Strong Candidate Gene

ObjectiveGlycine regulates glutamatergic neurotransmission, and several papers have reported the relationship between glycine and schizophrenia. The dysbindin-1 (DTNBP1: dystrobrevin-binding protein 1) gene is related to glutamatergic neurotransmission and has been found to be a strong candidate gene for schizophrenia. In this study, we clarified the relationship between dysbindin, glutamate, and glycine with in vivo microdialysis methods.MethodsWe measured extracellular glycine and glutamate levels in the striatum of sandy (sdy) mice using in vivo microdialysis methods. Sdy mice express no dysbindin protein owing to a deletion in the dysbindin-1 gene. In addition, we measured changes in those amino acids after methamphetamine (METH) administration.ResultsThe basal levels of extracellular glycine and glutamate in the striatum of sdy mice were elevated. These extracellular glutamate levels decreased gradually after METH administration and were not subsequently different from those of wild-type mice.ConclusionsThese results suggest that dysbindin might modulate glycine and glutamate release in vivo.

scholarly journals Brain-Specific SNAP-25 Deletion Leads to Elevated Extracellular Glutamate Level and Schizophrenia-Like Behavior in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Hua Yang ◽  
Mengjie Zhang ◽  
Jiahao Shi ◽  
Yunhe Zhou ◽  
Zhipeng Wan ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Mouse Model ◽  
Glutamate Release ◽  
Critical Role ◽  
Conditional Knockout ◽  
Snare Complex ◽  
Extracellular Glutamate ◽  
Glutamate Level

Several studies have associated reduced expression of synaptosomal-associated protein of 25 kDa (SNAP-25) with schizophrenia, yet little is known about its role in the illness. In this paper, a forebrain glutamatergic neuron-specific SNAP-25 knockout mouse model was constructed and studied to explore the possible pathogenetic role of SNAP-25 in schizophrenia. We showed that SNAP-25 conditional knockout (cKO) mice exhibited typical schizophrenia-like phenotype. A significantly elevated extracellular glutamate level was detected in the cerebral cortex of the mouse model. Compared with Ctrls, SNAP-25 was dramatically reduced by about 60% both in cytoplasm and in membrane fractions of cerebral cortex of cKOs, while the other two core members of SNARE complex: Syntaxin-1 (increased ~80%) and Vamp2 (increased ~96%) were significantly increased in cell membrane part. Riluzole, a glutamate release inhibitor, significantly attenuated the locomotor hyperactivity deficits in cKO mice. Our findings provide in vivo functional evidence showing a critical role of SNAP-25 dysfunction on synaptic transmission, which contributes to the developmental of schizophrenia. It is suggested that a SNAP-25 cKO mouse, a valuable model for schizophrenia, could address questions regarding presynaptic alterations that contribute to the etiopathophysiology of SZ and help to consummate the pre- and postsynaptic glutamatergic pathogenesis of the illness.

scholarly journals Primary structure requirements for correct sorting of the yeast mitochondrial protein ADH III to the yeast mitochondrial matrix space.

1987 ◽  
Vol 7 (1) ◽  
pp. 294-304 ◽  
Author(s):  
D Pilgrim ◽  
E T Young
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Proteolytic Processing ◽  
Mitochondrial Matrix ◽  
Wild Type ◽  
Mature Form ◽  
Amino Terminal ◽  
The Matrix

Alcohol dehydrogenase isoenzyme III (ADH III) in Saccharomyces cerevisiae, the product of the ADH3 gene, is located in the mitochondrial matrix. The ADH III protein was synthesized as a larger precursor in vitro when the gene was transcribed with the SP6 promoter and translated with a reticulocyte lysate. A precursor of the same size was detected when radioactively pulse-labeled proteins were immunoprecipitated with anti-ADH antibody. This precursor was rapidly processed to the mature form in vivo with a half-time of less than 3 min. The processing was blocked if the mitochondria were uncoupled with carbonyl cyanide m-chlorophenylhydrazone. Mutant enzymes in which only the amino-terminal 14 or 16 amino acids of the presequence were retained were correctly targeted and imported into the matrix. A mutant enzyme that was missing the amino-terminal 17 amino acids of the presequence produced an active enzyme, but the majority of the enzyme activity remained in the cytoplasmic compartment on cellular fractionation. Random amino acid changes were produced in the wild-type presequence by bisulfite mutagenesis of the ADH3 gene. The resulting ADH III protein was targeted to the mitochondria and imported into the matrix in all of the mutants tested, as judged by enzyme activity. Mutants containing amino acid changes in the carboxyl-proximal half of the ADH3 presequence were imported and processed to the mature form at a slower rate than the wild type, as judged by pulse-chase studies in vivo. The unprocessed precursor appeared to be unstable in vivo. It was concluded that only a small portion of the presequence contains the necessary information for correct targeting and import. Furthermore, the information for correct proteolytic processing of the presequence appears to be distinct from the targeting information and may involve secondary structure information in the presequence.

scholarly journals Interaction of wild-type signal sequences and their charged variants with model and natural membranes

1993 ◽  
Vol 293 (1) ◽  
pp. 43-49 ◽  
Author(s):  
N M Rao ◽  
R Nagaraj
Keyword(s):  
Amino Acids ◽  
Synthetic Peptides ◽  
Model Membranes ◽  
Signal Peptides ◽  
Wild Type ◽  
Signal Sequences ◽  
Hydrophobic Region ◽  
Phospholipases A2 ◽  
Charged Amino Acids

The interaction of synthetic peptides corresponding to wild-type signal sequences, and their mutants having charged amino acids in the hydrophobic region, with model and natural membranes has been studied. At high peptide concentrations, i.e. low lipid/peptide ratios, the signal peptides cause release of carboxyfluorescein (CF) from model membranes with lipid compositions corresponding to those of translocation-competent as well as translocation-incompetent membranes. Interestingly, mutant sequences, which were non-functional in vivo, caused considerable release of CF compared with the wild-type sequences. Both wild-type and mutant signal sequences perturb model membranes even at lipid/peptide ratios of 1000:1, as indicated by the activities of phospholipases A2, C and D. These studies indicate that such mutant signals are non-functional not because of their inability to interact with membranes, but due to defective targeting to the membrane. The signal peptides inhibit phospholipase C activity in microsomes, uncouple oxidative phosphorylation in mitochondria and increase K+ efflux from erythrocytes, and one of the mutant sequences is a potent degranulator of the mast cells. Both wild-type and mutant signal sequences have the ability to perturb vesicles of various lipid compositions. With respect to natural membranes, the peptides do not show any bias towards translocation-competent membranes.

scholarly journals Extensive mutagenesis of a transcriptional activation domain identifies single hydrophobic and acidic amino acids important for activation in vivo.

1997 ◽  
Vol 17 (1) ◽  
pp. 115-122 ◽  
Author(s):  
M B Sainz ◽  
S A Goff ◽  
V L Chandler
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transcriptional Activation ◽  
Carboxyl Terminus ◽  
Wild Type ◽  
Activation Domain ◽  
Hydrophobic Residues ◽  
Transcriptional Activation Domain ◽  
Acidic Amino Acids

C1 is a transcriptional activator of genes encoding biosynthetic enzymes of the maize anthocyanin pigment pathway. C1 has an amino terminus homologous to Myb DNA-binding domains and an acidic carboxyl terminus that is a transcriptional activation domain in maize and yeast cells. To identify amino acids critical for transcriptional activation, an extensive random mutagenesis of the C1 carboxyl terminus was done. The C1 activation domain is remarkably tolerant of amino acid substitutions, as changes at 34 residues had little or no effect on transcriptional activity. These changes include introduction of helix-incompatible amino acids throughout the C1 activation domain and alteration of most single acidic amino acids, suggesting that a previously postulated amphipathic alpha-helix is not required for activation. Substitutions at two positions revealed amino acids important for transcriptional activation. Replacement of leucine 253 with a proline or glutamine resulted in approximately 10% of wild-type transcriptional activation. Leucine 253 is in a region of C1 in which several hydrophobic residues align with residues important for transcriptional activation by the herpes simplex virus VP16 protein. However, changes at all other hydrophobic residues in C1 indicate that none are critical for C1 transcriptional activation. The other important amino acid in C1 is aspartate 262, as a change to valine resulted in only 24% of wild-type transcriptional activation. Comparison of our C1 results with those from VP16 reveal substantial differences in which amino acids are required for transcriptional activation in vivo by these two acidic activation domains.

scholarly journals The anti-inflammatory peptide Ac-SDKP is released from thymosin-β4 by renal meprin-α and prolyl oligopeptidase

2016 ◽  
Vol 310 (10) ◽  
pp. F1026-F1034 ◽  
Author(s):  
Nitin Kumar ◽  
Pablo Nakagawa ◽  
Branislava Janic ◽  
Cesar A. Romero ◽  
Morel E. Worou ◽  
...  
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Plasma Concentrations ◽  
Potential Candidate ◽  
Thymosin Β4 ◽  
Wild Type ◽  
Prolyl Oligopeptidase ◽  
Anti Inflammatory

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a natural tetrapeptide with anti-inflammatory and antifibrotic properties. Previously, we have shown that prolyl oligopeptidase (POP) is involved in the Ac-SDKP release from thymosin-β4 (Tβ4). However, POP can only hydrolyze peptides shorter than 30 amino acids, and Tβ4 is 43 amino acids long. This indicates that before POP hydrolysis takes place, Tβ4 is hydrolyzed by another peptidase that releases NH2-terminal intermediate peptide(s) with fewer than 30 amino acids. Our peptidase database search pointed out meprin-α metalloprotease as a potential candidate. Therefore, we hypothesized that, prior to POP hydrolysis, Tβ4 is hydrolyzed by meprin-α. In vitro, we found that the incubation of Tβ4 with both meprin-α and POP released Ac-SDKP, whereas no Ac-SDKP was released when Tβ4 was incubated with either meprin-α or POP alone. Incubation of Tβ4 with rat kidney homogenates significantly released Ac-SDKP, which was blocked by the meprin-α inhibitor actinonin. In addition, kidneys from meprin-α knockout (KO) mice showed significantly lower basal Ac-SDKP amount, compared with wild-type mice. Kidney homogenates from meprin-α KO mice failed to release Ac-SDKP from Tβ4. In vivo, we observed that rats treated with the ACE inhibitor captopril increased plasma concentrations of Ac-SDKP, which was inhibited by the coadministration of actinonin (vehicle, 3.1 ± 0.2 nmol/l; captopril, 15.1 ± 0.7 nmol/l; captopril + actinonin, 6.1 ± 0.3 nmol/l; P < 0.005). Similar results were obtained with urinary Ac-SDKP after actinonin treatment. We conclude that release of Ac-SDKP from Tβ4 is mediated by successive hydrolysis involving meprin-α and POP.

scholarly journals Disparate Phenotypes Resulting from Mutations of a Single Histidine in Switch II of Geobacillus stearothermophilus Translation Initiation Factor IF2

2020 ◽  
Vol 21 (3) ◽  
pp. 735
Author(s):  
Jerneja Tomsic ◽  
Arianna Smorlesi ◽  
Enrico Caserta ◽  
Anna Maria Giuliodori ◽  
Cynthia L. Pon ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Viability ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Geobacillus Stearothermophilus ◽  
Wild Type ◽  
Initiation Complex ◽  
Structural Alterations

The conserved Histidine 301 in switch II of Geobacillus stearothermophilus IF2 G2 domain was substituted with Ser, Gln, Arg, Leu and Tyr to generate mutants displaying different phenotypes. Overexpression of IF2H301S, IF2H301L and IF2H301Y in cells expressing wtIF2, unlike IF2H301Q and IF2H301R, caused a dominant lethal phenotype, inhibiting in vivo translation and drastically reducing cell viability. All mutants bound GTP but, except for IF2H301Q, were inactive in ribosome-dependent GTPase for different reasons. All mutants promoted 30S initiation complex (30S IC) formation with wild type (wt) efficiency but upon 30S IC association with the 50S subunit, the fMet-tRNA reacted with puromycin to different extents depending upon the IF2 mutant present in the complex (wtIF2 ≥ to IF2H301Q > IF2H301R >>> IF2H301S, IF2H301L and IF2H301Y) whereas only fMet-tRNA 30S-bound with IF2H301Q retained some ability to form initiation dipeptide fMet-Phe. Unlike wtIF2, all mutants, regardless of their ability to hydrolyze GTP, displayed higher affinity for the ribosome and failed to dissociate from the ribosomes upon 50S docking to 30S IC. We conclude that different amino acids substitutions of His301 cause different structural alterations of the factor, resulting in disparate phenotypes with no direct correlation existing between GTPase inactivation and IF2 failure to dissociate from ribosomes.

scholarly journals Mice Lacking Components of Adaptive Immunity Show Increased Brucella abortus virB Mutant Colonization

2007 ◽  
Vol 75 (6) ◽  
pp. 2965-2973 ◽  
Author(s):  
Hortensia García Rolán ◽  
Renée M. Tsolis
Keyword(s):  
Adaptive Immunity ◽  
Brucella Abortus ◽  
Mononuclear Phagocytes ◽  
Wild Type ◽  
Adaptive Immune ◽  
Type Iv ◽  
Absolute Requirement ◽  
The Relationship

ABSTRACT The Brucella abortus type IV secretion system (T4SS), encoded by the virB genes, is essential for survival in mononuclear phagocytes in vitro. In the mouse model, a B. abortus virB mutant was initially able to colonize the spleen at the level of the wild type for approximately 3 to 5 days, which coincided with the development of adaptive immunity. To investigate the relationship between survival in macrophages cultivated in vitro and persistence in tissues in vivo, we tested the ability of mutant mice lacking components of adaptive immunity to eliminate the virB mutant from the spleen during a mixed infection with the B. abortus wild type. Ifng −/− or β 2 m −/− mice were able to clear the virB mutant to the same degree as control mice. However, spleens of Rag1 −/− mice and Igh6 −/− mice were more highly colonized by the virB mutant than control mice after 14 to 21 days, suggesting that, in these mice, there is not an absolute requirement for the T4SS to mediate persistence of B. abortus in the spleen. Macrophages isolated from Igh6 −/− mice killed the virB mutant to the same extent as macrophages from control mice, showing that the reduced ability of these mice to clear the virB mutant from the spleen does not correlate with diminished macrophage function in vitro. These results show that in the murine model host, the T4SS is required for persistence beyond 3 to 5 days after infection and suggest that the T4SS may contribute to evasion of adaptive immune mechanisms by B. abortus.

P95 MRAS – A STRONG CANDIDATE GENE (SCG) FOR CORONARY ARTERY DISEASE (CAD)

2010 ◽  
Vol 11 (2) ◽  
pp. 36
Author(s):  
J. Freyer ◽  
A.K. Wagner ◽  
H. Schunkert ◽  
J.-J. Zwaginga ◽  
Z. Aherrahrou ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Candidate Gene ◽  
Artery Disease ◽  
Strong Candidate ◽  
Strong Candidate Gene

scholarly journals The Leishmania major LACK Antigen with an Immunodominant Epitope at Amino Acids 156 to 173 Is Not Required for Early Th2 Development in BALB/c Mice

2004 ◽  
Vol 72 (12) ◽  
pp. 6924-6931 ◽  
Author(s):  
Ben L. Kelly ◽  
Richard M. Locksley
Keyword(s):  
Amino Acids ◽  
T Cells ◽  
Leishmania Major ◽  
Cell Receptor ◽  
Interleukin 4 ◽  
Wild Type ◽  
Immunodominant Epitope ◽  
Fusion Construct ◽  
Th2 Immune Response

ABSTRACT The Leishmania major LACK antigen contains an immunodominant epitope at amino acids 156 to 173 (LACK156-173) that is believed to nucleate the pathological Th2 immune response in susceptible BALB/c mice. To test this hypothesis, we generated L. major parasites that express a mutated LACK that fails to activate Vβ4/Vα8 T-cell receptor transgenic T cells specific for this epitope. Although mutant parasites attenuated the expansion of endogenous LACK-specific, interleukin-4 (IL-4)-expressing, CD4 T cells compared to wild-type parasites in vivo, the overall frequency of IL-4 and gamma interferon-secreting lymphocytes was similar to that elicited by wild-type L. major. Mutant parasites demonstrated diminished amastigote viability and delayed lesion development in mice, although parasites could be recovered over 200 days after infection. Complementation with a wild-type lack fusion construct partially rescued these defects, indicating a role for endogenous LACK in parasitism. Mice inoculated with mutant parasites were not protected against subsequent infection with wild-type L. major.

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