PKA catalytic subunit compartmentation regulates contractile and hypertrophic responses to β-adrenergic signaling.
PKA catalytic subunit compartmentation regulates contractile and hypertrophic responses to β-adrenergic signaling.
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DOI：
10.1016/j.yjmcc.2013.11.001
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发表时间：
2014-01
影响因子：
5
通讯作者：
Saucerman, Jeffrey J.
中科院分区：
文献类型：
--
作者：
Yang, Jason H.;Polanowska-Grabowska, Renata K.;Smith, Jeffrey S.;Shields, Charles W.;Saucerman, Jeffrey J.
β-adrenergic signaling is spatiotemporally heterogeneous in the cardiac myocyte, conferring exquisite control to sympathetic stimulation. Such heterogeneity drives the formation of protein kinase A (PKA) signaling microdomains, which regulate Ca2+ handling and contractility. Here, we test the hypothesis that the nucleus independently comprises a PKA signaling microdomain regulating myocyte hypertrophy. Spatially-targeted FRET reporters for PKA activity identified slower PKA activation and lower isoproterenol sensitivity in the nucleus (t50 = 10.60±0.68 min; EC50 = 89.00 nmol/L) than in the cytosol (t50 = 3.71±0.25 min; EC50 = 1.22 nmol/L). These differences were not explained by cAMP or AKAP-based compartmentation. A computational model of cytosolic and nuclear PKA activity was developed and predicted that differences in nuclear PKA dynamics and magnitude are regulated by slow PKA catalytic subunit diffusion, while differences in isoproterenol sensitivity are regulated by nuclear expression of protein kinase inhibitor (PKI). These were validated by FRET and immunofluorescence. The model also predicted differential phosphorylation of PKA substrates regulating cell contractility and hypertrophy. Ca2+ and cell hypertrophy measurements validated these predictions and identified higher isoproterenol sensitivity for contractile enhancements (EC50 = 1.84 nmol/L) over cell hypertrophy (EC50 = 85.88 nmol/L). Over-expression of spatially targeted PKA catalytic subunit to the cytosol or nucleus enhanced contractile and hypertrophic responses, respectively. We conclude that restricted PKA catalytic subunit diffusion is an important PKA compartmentation mechanism and the nucleus comprises a novel PKA signaling microdomain, insulating hypertrophic from contractile β-adrenergic signaling responses.
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DOI：
10.1083/jcb.201105063
发表时间：
2011-10-31
期刊：
The Journal of cell biology
影响因子：
--
作者：
Backs J;Worst BC;Lehmann LH;Patrick DM;Jebessa Z;Kreusser MM;Sun Q;Chen L;Heft C;Katus HA;Olson EN
通讯作者：
Olson EN
影响因子：
4.8
作者：
Gerits, Nancy;Mikalsen, Theresa;Moens, Ugo
通讯作者：
Moens, Ugo
影响因子：
20.1
作者：
Fink, MA;Zakhary, DR;Bond, M
通讯作者：
Bond, M
影响因子：
2.7
作者：
Chen, Y;Periasamy, A
通讯作者：
Periasamy, A
DOI：
10.1083/jcb.104.2.189
发表时间：
1987-02
期刊：
The Journal of cell biology
影响因子：
--
作者：
Finlay DR;Newmeyer DD;Price TM;Forbes DJ
通讯作者：
Forbes DJ