CREATINE KINASE AND ENERGY METABOLISM HOMEOSTASIS

研究：能源储存、维护和利用对 细胞和肌肉功能。一直以来，人们认为肌酸激酶 在这一过程中发挥着至关重要的作用，提供了一种“能源储备” 功能，然而，补偿机制和分子反应 肌酸激酶系统的缺陷还没有完全被了解。 基于对肌酸激酶系统的传统理解 预计缺乏M肌酸激酶的动物将会严重 受损的或无法生存的。令人惊讶的是，最近对心脏和心脏的研究 不表达M-肌酸激酶的小鼠骨骼肌表现为 在静息状态下或在低ATP流量的情况下， 这表明这不是逃亡案。当其中一只老鼠的心脏 接受急性异丙肾上腺素输注(高三磷酸腺苷流量)， 似乎是三磷酸腺苷和磷酸肌酸的“解偶联”。这个 这一提议的假设是M-肌酸激酶活性是 维持心肌能量代谢动态平衡的关键 在高通量应力状态下。申请人患上了一种孤立的 灌流的小鼠心脏制剂，他将在其中应用 整合尖端生物化学的多学科方法 技术(31P核磁共振波谱)、生理和分子技术 研究以下具体目标：L)是三磷酸腺苷和三磷酸腺苷的浓度 肌酸激酶纯合子在心脏中解偶联的磷酸肌酸 在高通量而不是低通量压力下的基因敲除小鼠？2) 肌细胞内磷酸肌酸浓度与三磷酸腺苷的偶联 受到低和高磁通胁迫的基因的过度表达 肌酸激酶同工酶或肌酸转运蛋白？3) 功能性肌酸激酶的缺失改变其他蛋白的表达 基因作为M-肌酸激酶纯合子敲除的代偿机制 小鼠心脏在基础状态和低、高状态下的变化 通量压力？

The Research: Energy storage, maintenance and utilization is critical to cellular and muscle function. It has been thought that creatine kinase plays a crucial role in this process by providing an "energy reserve" function, however the compensatory mechanisms and molecular responses to deficiencies of the creatine kinase system are incompletely understood. Based on the traditional understanding of the creatine kinase system one would expect that animals lacking M creatine kinase would be severely impaired or unable to survive. Surprisingly, recent studies of cardiac and skeletal muscle of mice which express no M creatine kinase, demonstrate no noticeable abnormalities at rest, or under conditions of low ATP flux, suggesting that this is not flee case. When a heart from one of these mice is subjected to acute isoproterenol infusion (high ATP flux), there appears to be an "uncoupling" of ATP and creatine phosphate. The hypothesis of this proposal is that M creatine kinase activity is of crucial importance in maintaining myocardial energy metabolism homeostasis in high flux stress states. The applicant has developed an isolated perfused mouse heart preparation, to which he will apply a multidisciplinary approach integrating sophisticated biochemical techniques (31P NMR spectroscopy), physiologic and molecular techniques to study the following Specific Aims: l) Are concentrations of ATP and creatine phosphate uncoupled in hearts from M creatine kinase homozygous knockout mice under high flux but not under low flux stress? 2) Can the coupling of ATP to creatine phosphate concentrations in muscle cells subjected to low and high flux stress be altered by the over-expression of creatine kinase isoenzymes or of the creatine transporter? 3) Does the absence of functional M creatine kinase alter the expression of other genes as a compensatory mechanism in M creatine kinase homozygous knockout mouse hearts under basal conditions and under conditions of low and high flux stress?