甲状腺过氧化酶的二硫化键是亚细胞局部化,蛋白酶依赖性降解和酶活性的关键元素
Hajime Iwasaki1, Hirotsugu Suwanai1, Fumiyoshi Yakou1
1Department of Diabetes, Metabolism, and Endocrinology, Tokyo Medical University, Tokyo, Japan.
甲状腺过氧化酶 (TPO) 的二硫化键中的突变会导致先天性甲状腺功能低下症 (CH). 所有12个TPO二硫化键对酶活性至关重要,它们的破坏导致错误折叠和降解.
科学领域:
- 生物化学 生化学
- 分子生物学分子生物学
- 内分泌学 在内分泌学.
背景情况:
- 先天性甲状腺功能低下症 (CH) 是一种经常与影响甲状腺激素合成的遗传突变相关的疾病.
- 甲状腺过氧化酶 (TPO) 是甲状腺激素生产中的关键酶,其功能依赖于特定的结构元素.
- 形成二硫化键的氨酸残留物对蛋白质结构和功能至关重要,但它们在TPO中的特定作用尚未完全阐明.
研究的目的:
- 研究甲状腺过氧化酶 (TPO) 中二硫化键的功能意义.
- 分析氨酸突变在二硫化键内对TPO活性,局部化和稳定性的影响.
- 了解在先天性甲状腺功能低下症中TPO功能障碍背后的分子机制.
主要方法:
- 用局部导向的突变生成来创造TPO突变 (C655F,C825R) 和其他囊替代物.
- 用TPO结构转染了HEK293细胞,并通过Westernblotting评估了蛋白质表达.
- 使用Amplex Red测定法测量了TPO酶活性.
- 亚细胞局部通过免疫细胞化学和流细胞测量来确定.
- 使用in silico分析来预测二硫化物键的位置.
主要成果:
- 突变C655F和C825R显著降低了TPO活性和蛋白质表达.
- 蛋白质酶抑制 (MG132) 增加了TPO表达,但不增加活性,这表明降解是关键问题.
- 突变TPO蛋白显示细胞表面局部化减少.
- 所有12个预测的二硫化物债券对于TPO活动至关重要,其影响取决于债券的位置.
- 突变导致蛋白质错误折叠,降解增加和膜插入受损.
结论:
- 在TPO中,所有12个二硫化物键对于其酶活性和正常功能至关重要.
- 破坏TPO二硫化键导致蛋白质错误折叠,增强降解和不正确的亚细胞定位.
- 这些发现为TPO缺陷引起的先天性甲状腺功能低下症的分子基础提供了关键的见解.
更多相关视频
03:09Author Spotlight: Advancing Structural and Biochemical Studies of Proteins Through Thermal Shift Assays
Published on: August 9, 2024
09:37Combining Non-reducing SDS-PAGE Analysis and Chemical Crosslinking to Detect Multimeric Complexes Stabilized by Disulfide Linkages in Mammalian Cells in Culture
Published on: May 2, 2019
相关概念视频
Protein Modifications in the RER
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
The Proteasome Structure
The proteasome is an...
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Preparation and Reactions of Thiols
