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Abstract: The subunit structure of brain glutamate decarboxylase in cerebellum was investigated by using gel electrophoresis and antisera that specifically recognize the individual isoforms of brain glutamate decarboxylase (termed GAD65 and GAD67 ). The antisera were prepared against peptides that corresponded to amino acid sequences specific to each isoform. Each antiserum reacted specifically with the appropriate peptide in an ELISA and with the appropriate form of GAD on immunoblots. Nondenaturing gradient gel electrophoresis indicated that GAD is principally multimeric with monomeric forms comprising <3% of the total. Immunoprecipitation and immunoaffinity chromatography experiments were performed with antisera W624 and W883, which were prepared against peptides specific to GAD65 and GAD67 , respectively. Immunoprecipitates prepared from cerebellar supernatants with W624 contained both GAD65 and GAD67 , whereas some GAD67 was left in the supernatant. In a similar manner, immunoprecipitates prepared with W883 contained both GAD65 and GAD67 , whereas some GAD65 remained in the supernatant. In addition, immunoaffinity columns prepared with either W624 or W883 retained both GAD65 and GAD67 even after extensive washing. These results are consistent with the presence of heteromultimers of GAD65 and GAD67 in cerebellum in addition to homomers of each form. 相似文献
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Zhang Q Zulfiqar F Xiao X Riazuddin SA Ahmad Z Caruso R MacDonald I Sieving P Riazuddin S Hejtmancik JF 《Human genetics》2007,122(3-4):293-299
Mutation in the PROM1 gene previously has been identified in one family with retinal degeneration for which neither ERG recordings
nor detailed information about visual impairment is available. A large family with multiple individuals affected by retinal
degeneration was ascertained in the Punjab province of Pakistan. The visual acuity of all affected patients in the family
was severely compromised beginning in early childhood. The retinal disease in this family is a severe form of retinitis pigmentosa
(RP) accompanied by macular degeneration. Fundus changes advanced with age. Choriocapillaris atrophy and posterior RPE atrophy
were obvious allowing visualization of the large choroidal vessels in patients over 40 years of age. Rod and cone responses
on ERG recordings were extinguished in patient’s teens. A genome-wide scan mapped the disease to a 34.7 cM region of chromosome
4p14–p16 between D4S1599 and D4S405. A maximum lod score of 3.96 with D4S403 and D4S391 is seen at θ = 0. Sequence analysis
of PROM1 located in the linkage interval identified a c.1726C>T homozygous transition in exon 15: resulting in p.Gln576X in
the translated protein. This mutation is found in a homozygous state in all six affected individuals and was heterozygous
in five of the six unaffected family members examined. The mutation was not detected in 192 chromosomes of unrelated control
individuals of the same ethnicity and from the same region. This delineates the phenotypic characteristics of retinopathy
caused by mutations in PROM1.
Qingjiong Zhang, Fareeha Zulfiqar, Xueshan Xiao, Sheikh Riazuddin and J. Fielding Hejtmancik contributed equally. 相似文献
84.
A Mutation in the SH2 domain of STAT2 prolongs tyrosine phosphorylation of STAT1 and promotes type I IFN-induced apoptosis 下载免费PDF全文
Scarzello AJ Romero-Weaver AL Maher SG Veenstra TD Zhou M Qin A Donnelly RP Sheikh F Gamero AM 《Molecular biology of the cell》2007,18(7):2455-2462
Type I interferons (IFN-alpha/beta) induce apoptosis in certain tumor cell lines but not others. Here we describe a mutation in STAT2 that confers an apoptotic effect in tumor cells in response to type I IFNs. This mutation was introduced in a conserved motif, PYTK, located in the STAT SH2 domain, which is shared by STAT1, STAT2, and STAT3. To test whether the tyrosine in this motif might be phosphorylated and affect signaling, Y631 of STAT2 was mutated to phenylalanine (Y631F). Although it was determined that Y631 was not phosphorylated, the Y631F mutation conferred sustained signaling and induction of IFN-stimulated genes. This prolonged IFN response was associated with sustained tyrosine phosphorylation of STAT1 and STAT2 and their mutual association as heterodimers, which resulted from resistance to dephosphorylation by the nuclear tyrosine phosphatase TcPTP. Finally, cells bearing the Y631F mutation in STAT2 underwent apoptosis after IFN-alpha stimulation compared with wild-type STAT2. Therefore, this mutation reveals that a prolonged response to IFN-alpha could account for one difference between tumor cell lines that undergo IFN-alpha-induced apoptosis compared with those that display an antiproliferative response but do not die. 相似文献
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Heidari Reza Farajzadeh Sheikh Ahmad Hashemzadeh Mohammad Farshadzadeh Zahra Salmanzadeh Shokrollah Saki Morteza 《Molecular biology reports》2022,49(5):3811-3822
Molecular Biology Reports - This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains... 相似文献
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Phospholipids are known to influence fibril formation of amyloid beta (Aβ) peptide. Here, we show that lysophosphatidylcholine (LPC), a polar phospholipid, enhances Aβ(1-42) fibril formation, by decreasing the lag time and the critical peptide concentration required for fibril formation, and increasing the fibril elongation rate. Conversely, LPC did not have an enhancing effect on Aβ(1-40) fibril formation, and appeared to be inhibitory. Tyrosine fluorescence spectroscopy showed that LPC altered the fluorescence spectra of Aβ(1-40) and Aβ(1-42) in opposite ways. Further, 8-anilino-1-naphthalene sulfonic acid fluorescence spectroscopy showed that LPC significantly increased the hydrophobicity of Aβ(1-42), but not of Aβ(1-40). Tris-tricine gradient SDS/PAGE revealed that LPC increased the formation of higher-molecular-weight species of Aβ(1-42), including trimers and tetramers. LPC had no such effect on Aβ(1-40), and thus may specifically influence the oligomerization and nucleation processes of Aβ(1-42) in a manner dependent on its native structure. Dot-blot assays confirmed that LPC induced Aβ(1-42) oligomer formation at an early time point. Thus our results indicate that LPC specifically enhances the formation of Aβ(1-42) fibrils, the main component of senile plaques in Alzheimer's disease patients, and may be involved in Alzheimer's disease pathology. 相似文献
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