Role of DAKAPs in Mitochondrial Function

DAKAP 在线粒体功能中的作用

• 批准号: 6622377
• 负责人: Kenneth M Humphries
• 金额: $ 2.6万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6622377
• 关键词: A kinase anchoring protein; G protein; cyclic AMP; cytochrome c; intracellular transport; laboratory mouse; mitochondria; phosphoproteins; phosphorylation; protein kinase A; protein structure function; protein transport

Relatively little is known about second messenger signaling to mitochondria. In recent years though, a number of substrates have been identified in this organelle that are phosphorylated in a cAMP-dependent manner. These substrates have been identified in this organelle that are phosphorylated in a cAMP-dependent manner. These substrates including electron transport chain components and the proapoptotic protein, BAD, suggest a physiological role for cAMP-dependant protein kinase (PKA) in mitochondria. Experiments performed in the Taylor laboratory have identified two new AKAPs (D=AKAPs) are localized to the mitochondria. D-AKAP1 contains 30 amino acids at the NH2- terminus that are sufficient for targeting to the outer mitochondrial membrane, while preliminary studies suggest D-AKAP2 localizes to the matrix. Interestingly, D-AKAP2 also contains two putative PGS domains, sites capable of binding Galpha subunits and leading to speculation that D-AKAP2 may be a scaffolding protein capable of co- localizing multiple signaling molecules. We hypothesize that PKA's role in altering specific mitochondrial functions is mediated by its association with these novel anchoring proteins. To test this hypothesis, this research proposes to identify substrates phosphorylated by PKA as a consequence of this association with the AKAPs. Because of the biochemical differences between RI and RII isoforms, the relative effect of PKA on mitochondrial function may be a function of which isoform is bound to the anchoring protein. This research will thus seek to determine the relative significance of RI versus RII isoform anchoring in mitochondria. Finally, experiments will be performed to determine what proteins, in addition to PKA, are bound to D-AKAP2 in mitochondria.

关于线粒体的第二信使信号传导相对鲜为人知。但是，近年来，在该细胞器中已经确定了许多以营地依赖性方式磷酸化的底物。这些底物已在该细胞器中鉴定出来以营地依赖性方式磷酸化。这些底物在包括电子传输链成分和促凋亡蛋白的情况下，暗示了线粒体中cAMP依赖性蛋白激酶（PKA）的生理作用。在泰勒实验室进行的实验已经确定了两个新的AKAP（D = AKAP）位于线粒体上。 D-AKAP1在NH2-末端包含30个氨基酸，足以靶向线粒体外膜，而初步研究表明D-AKAP2定位于基质。有趣的是，D-AKAP2还包含两个推定的PGS结构域，能够结合Galpha亚基的位点，并导致人们猜测D-AKAP2可能是一种能够共同定位多个信号分子的脚手架蛋白。我们假设PKA在改变特定线粒体功能中的作用是由其与这些新型锚定蛋白的关联所介导的。为了检验这一假设，这项研究提议确定由PKA磷酸化的底物，这是由于这种与AKAP的关联而导致的。由于RI和RII同工型之间存在生化差异，因此PKA对线粒体功能的相对影响可能是同工型与锚定蛋白结合的函数。因此，这项研究将寻求确定RI与RII同工型在线粒体中的相对重要性。最后，将进行实验，以确定除PKA以外的蛋白质与线粒体中的D-AKAP2结合了哪些蛋白质。