首页>
外文期刊>The biochemical journal
>Attenuation of the hypoxia-induced protein kinase Cδ interaction with the ‘d’ subunit of F1Fo-ATP synthase in neonatal cardiac myocytes: implications for energy preservation and survival
【24h】
Attenuation of the hypoxia-induced protein kinase Cδ interaction with the ‘d’ subunit of F1Fo-ATP synthase in neonatal cardiac myocytes: implications for energy preservation and survival
pThe Fsub1/subFsubo/sub-ATP synthase provides most of the heart9s energy, yet events that alter its function during injury are poorly understood. Recently, we described a potent inhibitory effect on Fsub1/subFsubo/sub-ATP synthase function mediated by the interaction of PKCδ (protein kinase Cδ) with dFsub1/subFsubo/sub (‘d’ subunit of the Fsub1/subFsubo/sub-ATPase/ATP synthase). We have now developed novel peptide modulators which facilitate or inhibit the PKCδ–dFsub1/subFsubo/sub interaction. These peptides include HIV-Tat (transactivator of transcription) protein transduction and mammalian mitochondrial-targeting sequences. Pre-incubation of NCMs (neonatal cardiac myocyte) with 10 nM extracellular concentrations of the mitochondrial-targeted PKCδ–dFsub1/subFsubo/sub interaction inhibitor decreased Hx (hypoxia)-induced co-IP (co-immunoprecipitation) of PKCδ with dFsub1/subFsubo/sub by 40±9%, abolished Hx-induced inhibition of Fsub1/subFsubo/sub-ATPase activity, attenuated Hx-induced losses in Fsub1/subFsubo/sub-derived ATP and protected against Hx- and reperfusion-induced cell death. A scrambled-sequence (inactive) peptide, which contained HIV-Tat and mitochondrial-targeting sequences, was without effect. In contrast, the cell-permeant mitochondrial-targeted PKCδ–dFsub1/subFsubo/sub facilitator peptide, which we have shown previously to induce the PKCδ–dFsub1/subFsubo/sub co-IP, was found to inhibit Fsub1/subFsubo/sub-ATPase activity to an extent similar to that caused by Hx alone. The PKCδ–dFsub1/subFsubo/sub facilitator peptide also decreased ATP levels by 72±18% under hypoxic conditions in the presence of glycolytic inhibition. None of the PKCδ–dFsub1/subFsubo/sub modulatory peptides altered the inner mitochondrial membrane potential. Our studies provide the first evidence that disruption of the PKCδ–dFsub1/subFsubo/sub interaction using cell-permeant mitochondrial-targeted peptides attenuates cardiac injury resulting from prolonged oxygen deprivation./p
展开▼
机译：> F 1 F o -ATP合酶提供了心脏的大部分能量，但人们对其损伤期间改变其功能的事件了解甚少。最近，我们描述了由PKCδ（蛋白激酶Cδ）与dF 1的相互作用介导的对F 1 F o o -ATP合酶功能的有效抑制作用。 sub> F o （F 1 F o -ATPase / ATP合酶的“ d”亚基）。现在，我们已经开发出了新型的肽调节剂，可以促进或抑制PKCδ–dF 1 F o 相互作用。这些肽包括HIV-Tat（转录反式激活蛋白）蛋白转导和哺乳动物线粒体靶向序列。 NCM（新生儿心肌细胞）与10nM细胞外浓度的线粒体靶向PKCδ–dF 1 F o 相互作用抑制剂的预孵育降低了Hx（低氧）诱导的PKCδ与dF 1 F o 的共IP（共免疫沉淀）40±9％，消除了Hx对F 1 的抑制作用F o -ATPase活性，减弱Hx诱导的F 1 F o 来源的ATP的损失，并防御Hx和再灌注诱导的细胞死亡。包含HIV-Tat和线粒体靶向序列的加扰序列（无效）肽无效。相比之下，针对细胞渗透的线粒体靶向的PKCδ–dF 1 F o 促进肽，我们先前已经证明了它可以诱导PKCδ–dF 1 F o co-IP抑制F 1 F o -ATPase活性的程度与仅由Hx引起的程度相似。在低糖条件下，存在糖酵解抑制作用时，PKCδ–dF 1 F o 促进肽也使ATP水平降低了72±18％。 PKCδ–dF 1 F o 调节肽均未改变内线粒体膜电位。我们的研究提供了第一个证据，即使用细胞渗透性线粒体靶向肽破坏PKCδ–dF 1 F o 相互作用可减轻因长期缺氧导致的心脏损伤。
展开▼
