کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8298757 | 1537043 | 2014 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Stimulation of oxidative phosphorylation by calcium in cardiac mitochondria is not influenced by cAMP and PKA activity
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Stimulation of oxidative phosphorylation by calcium in cardiac mitochondria is not influenced by cAMP and PKA activity Stimulation of oxidative phosphorylation by calcium in cardiac mitochondria is not influenced by cAMP and PKA activity](/preview/png/8298757.png)
چکیده انگلیسی
Cardiac oxidative ATP generation is finely tuned to match several-fold increases in energy demand. Calcium has been proposed to play a role in the activation of ATP production via PKA phosphorylation in response to intramitochondrial cAMP generation. We evaluated the effect of cAMP, its membrane permeable analogs (dibutyryl-cAMP, 8-bromo-cAMP), and the PKA inhibitor H89 on respiration of isolated pig heart mitochondria. cAMP analogs did not stimulate State 3 respiration of Ca2 +-depleted mitochondria (82.2 ± 3.6% of control), in contrast to the 2-fold activation induced by 0.95 μM free Ca2 +, which was unaffected by H89. Using fluorescence and integrating sphere spectroscopy, we determined that Ca2 + increased the reduction of NADH (8%), and of cytochromes bH (3%), c1 (3%), c (4%), and a (2%), together with a doubling of conductances for Complex I + III and Complex IV. None of these changes were induced by cAMP analogs nor abolished by H89. In Ca2 +-undepleted mitochondria, we observed only slight changes in State 3 respiration rates upon addition of 50 μM cAMP (85 ± 9.9%), dibutyryl-cAMP (80.1 ± 5.2%), 8-bromo-cAMP (88.6 ± 3.3%), or 1 μM H89 (89.7 ± 19.9%) with respect to controls. Similar results were obtained when measuring respiration in heart homogenates. Addition of exogenous PKA with dibutyryl-cAMP or the constitutively active catalytic subunit of PKA to isolated mitochondria decreased State 3 respiration by only 5-15%. These functional studies suggest that alterations in mitochondrial cAMP and PKA activity do not contribute significantly to the acute Ca2 + stimulation of oxidative phosphorylation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1837, Issue 12, December 2014, Pages 1913-1921
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1837, Issue 12, December 2014, Pages 1913-1921
نویسندگان
Raul Covian, Stephanie French, Heather Kusnetz, Robert S. Balaban,