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Analysis of knockout mouse of a brain-specific H^+ transporter ASPT.

脑特异性H^转运蛋白ASPT敲除小鼠的分析。

基本信息

批准号：
14580763
负责人：
SHIMOKAWA Noriaki
金额：
$ 2.37万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14580763/
关键词：
extracellular acidosis ventral medullary surface of the medulla oblongata acidosis-induced genes nuclear transcription factors c-Jun NH_2-terminal kinase voltage-gated Ca^<2+> channels H^+-sensitivity Past-A ASPT H^+ sensitivity Acidos

项目摘要

We describe the role of c-Jun NH_2-terminal kinase(JNK) in regulation of gene transcription after an increase in extracellular H^+. When cells were incubated in low pH medium, the promotion of JNK phosphorylation and c-Jun expression was clearly observed in cells in an extracellular pH-and time-dependent manner. Activation of p38 and extracellular signal-regulated kinase 1/2 (ERK1/2) was extremely weak compared with that of JNK. An increase in extracellular H^+ led to enhanced nuclear translocation of phosphorylated JNK leading to augmentation of the transcriptional activity of c-Jun. Nimodipine, a blocker of voltage-gated Ca^<2+> ion channels, prevented the phosphorylation of JNK and expression of c-Jun in a dose-dependent manner. These results suggesta novel intracellular signalling pathway for H^+-induced c-Jun expression : an increase of extracellular H^+ induces JNK phosphorylation and c-Jun expression via partly extracellular Ca^<2+> influx through voltage-gated Ca^<2+> channels. … More We describe properties of gene expression, protein interaction and DNA binding activity of basic region leucine zipper(bZIP) transcription factor Maf and FosB during extracellular acidification. When cells were incubated with low pH medium, the expressions of small Maf proteins (MafG,MafK and MafF) and FosB were clearly increased in an extracellular pH-dependent manner and expressed transiently with a peak after 1-2 h after stimulation. Immunofluorescence and protein binding studies indicated that MafG was partially co-localized with FosB in the nucleus and MafG can form heterodimers with FosB at extracellular pH 7.40. Moreover, we found that MafG-FosB complexes are able to bind to AP-1 consensus sequence, TGACTCA. To investigate whether extracellular acidification influences to dimerization and DNA binding activity of MafG and FosB, extracellular pH of cultured cells was decreased from 7.40 to 6.80. The decrease in extracellular pH led to enhanced dimerization of MafG with FosB leading to augmentation of the DNA binding activity of the heterodimer to AP-1 consensus sequence. Moreover, extracellular acidification induces mRNA expression of matrix metalloproteinase-1, one of genes that are regulated by AP-1. These results suggest that MafG-FosB complexes are involved in transcriptional regulation in response to extracellular acidification. Less

我们描述了c-Jun氨基末端激酶(JNK)在细胞外H~+增加后基因转录调控中的作用。当细胞在低pH条件下孵育时，细胞内JNK磷酸化和c-Jun的表达明显增强，且呈细胞外pH和时间依赖性。与JNK相比，p38和细胞外信号调节蛋白1/2(ERK1/2)的激活非常弱。胞外H~(++)增加导致磷酸化JNK核转位增强，导致c-jun转录活性增强。电压门控性钙通道阻断剂尼莫地平以剂量依赖的方式抑制JNK的磷酸化和c-Jun的表达。这些结果提示了H~(++)诱导c-Jun表达的一种新的细胞内信号途径：胞外H~(++)通过电压门控的Ca~(2+)通道部分地内流，从而诱导JNK磷酸化和c-Jun表达。…此外，我们描述了碱性区域亮氨酸拉链(BZIP)转录因子Maf和FosB在胞外酸化过程中的基因表达、蛋白质相互作用和DNA结合活性的特性。低pH条件下，细胞内小分子MAF蛋白(MafG、MafK、Maff)和FosB的表达明显增加，并呈细胞外pH依赖性，刺激后1~2 h达高峰。免疫荧光和蛋白质结合研究表明，MafG与FosB部分共存于胞核，在胞外pH为7.40时，MafG与FosB可形成异二聚体。此外，我们还发现MafG-FosB复合体能够与AP-1共有序列TGACTCA结合。为了研究胞外酸化是否影响MafG和FosB的二聚化和DNA结合活性，将培养细胞的胞外pH从7.40降至6.80。胞外pH的降低导致MafG与FosB的二聚化增强，导致异源二聚体与AP-1共同序列的DNA结合活性增强。此外，胞外酸化诱导基质金属蛋白酶-1的mRNA表达，这是AP-1调节的基因之一。这些结果表明，MafG-FosB复合体参与了细胞外酸化反应的转录调控。较少