与α2亚单元相关的AMPK活性增加和PRKAG2心肌病变
Ferhaan Ahmad1, Michael Arad, Nicolas Musi
1Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, USA.
Circulation
|November 9, 2005
概括
通过激活α2-AMPK,PRKAG2突变会导致心肌病,导致糖原的积累. 在小鼠中抑制alpha2-AMPK逆转了心脏和导电异常,确定alpha2为关键介质.
科学领域:
- 生物化学 生物化学
- 心脏病学 心脏病学
- 遗传学 是一个遗传学.
背景情况:
- AMP激活蛋白激酶 (AMPK) 调节性玛2亚单元 (PRKAG2) 突变与人类心肌病症有关.
- 这种情况涉及心脏缩,预兴奋和糖原沉积.
- 在过度表达突变型PRKAG2 N488I (TGgamma2N488I) 的小鼠中模拟PRKAG2心肌病.
研究的目的:
- 研究alpha1和alpha2AMPK亚单元异型在PRKAG2心肌病中的作用.
- 为了确定抑制α2-关联的AMPK活性是否可以改善疾病表型.
主要方法:
- 利用过度表达主导负α2亚单元 (TGalpha2DN) 的转基因小鼠选择性抑制α2-AMPK活性.
- 产生的化合物-异合体TGgamma2N488I/TGalpha2DN小鼠.
- 评估了心电图,心脏功能,形态,运动能力和心脏糖原含量.
主要成果:
- 与TGgamma2N488I小鼠相比,复合异合性小鼠的α2-AMPK活性下降.
- TGalpha2DN转基因部分或完全使心电图,心脏功能,形态和运动能力正常化.
- TGgamma2N488I心脏表现出正常的休息能量酸盐,并在运动期间利用储存的糖原.
结论:
- PRKAG2 N488I突变不适当地激活AMPK,导致糖原积累和导电系统疾病.
- 积累的糖原作为能量来源,在运动期间保持收缩储备.
- 涉及alpha2子单元的AMPK复合体,而不是alpha1,是PRKAG2突变效应的主要媒介.
相关概念视频
mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
PI3K/mTOR/AKT Signaling Pathway
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a rapamycin-insensitive companion...
GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
Cardiomyopathy II: Dilated Cardiomyopathy
Dilated cardiomyopathy, or DCM, is a progressive myocardial disorder characterized by ventricular chamber dilation and contractile dysfunction.EtiologyVarious factors can cause DCM, including hypertension and heavy alcohol intake, which contribute to the weakening and enlargement of the heart muscle. Viral infections, such as Coxsackievirus B, adenoviruses, and influenza, can lead to DCM by causing inflammation and damage to heart tissue. Certain chemotherapeutic agents, including daunorubicin,...
Cardiomyopathy III: Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...


