Intracellular Degradation of a Mutant Serine : Pyruvate/Alanine : Glyoxylate Aminotransferase

突变丝氨酸的细胞内降解：丙酮酸/丙氨酸：乙醛酸转氨酶

• 批准号: 06454176
• 负责人: ICHIYAMA Arata
• 金额: $ 4.61万
• 依托单位: Hamamatsu University School of Medicine
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06454176/
• 关键词: serine : pyruvate aminotransferase; alanine : glyoxylate aminotransferase; primary hyperoxaluria type 1; mutant protein; energy-dependent proteolysis; 26S proteasomes; reticulocyte lysate; yeast mutant pre1-1; エネルギー症候性蛋白質分解; 酵母変異株prel-1; 蓚酸; エネ

We recently studied a primary hyperoxaluria type 1 case who belongs to the ENZ^-/CRM^- class, and his serine : pyruvate/alanine : glyoxylate aminotransferase (SPT/AGT) gene was found to have a homogygous point mutation in the middle of the coding region (a T to C mutation resulting in a Ser to Pro substitution at residue 205). Available evidence suggested that the enzyme deficiency is due to neither a defect in transcription nor one in translation, but is due, at least in part, to instability of the mutant SPT/AGT protein in cells. The mutant SPT/AGT was also degraded faster than normal in an in vitro system involving a rabbit reticulocyte lysate, and this reaction required ATP and Mg^<2+>. A well characterized ATP-hydrolysis-dependent proteolytic machinary in reticulocyte lysates is the ubiquitin-proteasome system, but immunodepletion of proreasomes or inclusion in the reaction mixture of peptide aldehyde proteasome inhibitors had no effect on the degradation of the mutant SPT/AGT in a reticulocyte lysate. In addition, the mutant SPT/AGT was not stabilized in a yeast mutant (per1-1) with defective proteasomes. These results indicate that the inherited mutant SPT/AGT is degraded ATP-hydrolysis-dependently without involvement of proteasomes. It is thus suggested that an energy-dependent proteolytic pathway other than that involving proteasomes participates in selective elimination of abnormal proteins generated in genetic disorders.

我们最近研究了1例原发性高尿酸血症1型患者，该患者属于ENZ^-/CRM^-型，其丝氨酸：丙酮酸/丙氨酸：乙醛酸氨基转移酶（SPT/AGT）基因在编码区中间有一个同型点突变（T → C突变导致第205位残基Ser → Pro）。现有的证据表明，酶的缺陷是由于既不是在转录也不是一个在翻译缺陷，但至少部分是由于突变的SPT/AGT蛋白在细胞中的不稳定性。在含有兔网织红细胞裂解物的体外系统中，突变型SPT/AGT的降解速度也比正常情况下快，而且该反应需要ATP和Mg^2+。网织红细胞裂解物中一个充分表征的ATP水解依赖性蛋白水解机制是泛素-蛋白酶体系统，但蛋白酶体的免疫耗竭或肽醛蛋白酶体抑制剂的反应混合物中的包含物对网织红细胞裂解物中突变SPT/AGT的降解没有影响。此外，突变体SPT/AGT在具有缺陷蛋白酶体的酵母突变体（per 1 -1）中不稳定。这些结果表明，遗传突变SPT/AGT降解ATP水解依赖性的蛋白酶体没有参与。因此，这表明，能量依赖性蛋白水解途径以外的蛋白酶体参与选择性消除异常蛋白质产生的遗传疾病。

项目成果

Kuniko Ishikawa: "A liver enzyme,Serine:Pyruvate/alanine:glyoxylate amino-transferase and its mutant in a primavy byperoxaluria type 1 case." Biochemistry of Vitamin B_6 and PQQ (eds,G.Marino,G.Sannia,F.Bossa),Birkhauser Verlag.337-341 (1994)

Kuniko Ishikawa：“1 型原发过草酸尿症病例中的肝酶、丝氨酸：丙酮酸/丙氨酸：乙醛酸氨基转移酶及其突变体。”

市山 新: "臨床DNA診断法(古庄敏行,井村裕夫,中込弥男,岡田伸太郎,湯浅保=,倉田毅編),原発性高蓚酸尿症1型(425-427)を分推執筆" 金原出版, (1996)

Arata Ichiyama：“临床DNA诊断方法（Toshiyuki Furusho，Hiroo Imura，Yao Nakagome，Shintaro Okada，Tamotsu Yuasa，Tsuyoshi Kurata，编辑），原发性高草酸尿症1型（425-427）的主要作者”Kanehara Publishing，（1996）

Sadaki Yokota: "Immunoelectron microscopic localization of peroxisomel enzymes in the bibrillar structures of rat liver peroxisomes induced by administration of acetylsalicylic acid" Acta Histochem.Cytochem.(関連研究). 28. 11-19 (1995)

Sadaki Yokota：“乙酰水杨酸诱导的大鼠肝脏过氧化物酶体双结构中过氧化物酶体酶的免疫电子显微镜定位”Acta Histochem.Cytochem.（相关研究）。

Toshiaki Suzuki: "Energy-dependent degradation of a matant serine:pyruvate/ulaxine:glyoxylate aminotransferase in a primary byperozaluna type I case" Intraclilat Protein Catabolism(Proceestings of the 10th ICOP Meeling)(eds.J.S.Bond and K.Suzuki). (in pre

Toshiaki Suzuki：“在原发性 byperozaluna I 型病例中，活性丝氨酸：丙酮酸/乌拉素：乙醛酸转氨酶的能量依赖性降解”Intraclilat 蛋白质分解代谢（第 10 届 ICOP Meeling 会议记录）（J.S.Bond 和 K.Suzuki 编）。

Toshiaki Suzuki: "Energy-dependent degradation of a mutant serine:pyravatel alanene:glyoxylate aminotransferase in a primary by peroxaluria type 1 case." Intracellular Protein Catabolism (eds.J.S.Bond,K,Suzuki). (印刷中). (1996)

Toshiaki Suzuki：“1 型过草酸尿症原发病例中突变丝氨酸：吡喃丙醇：乙醛酸转氨酶的能量依赖性降解”（J.S.Bond，K，Suzuki 编辑）（1996 年出版）。