β-Adrenergic regulation of cardiac type 2A protein phosphatase through phosphorylation of regulatory subunit B56δ at S573.
β-Adrenergic regulation of cardiac type 2A protein phosphatase through phosphorylation of regulatory subunit B56δ at S573.
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DOI：
10.1016/j.yjmcc.2017.12.016
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发表时间：
2018-03
影响因子：
5
通讯作者：
Avkiran M
中科院分区：
文献类型：
--
作者：
Ranieri A;Kemp E;Burgoyne JR;Avkiran M
2A型蛋白磷酸酶（PP2A）是丝氨酸/苏氨酸磷酸酶，由支架a亚基、调节B亚基和催化C亚基组成，并与多种心脏磷酸化蛋白的去磷酸化有关。B亚基决定亚细胞靶向性、底物特异性和催化活性，并且本身可以通过翻译后修饰进行调节。我们通过调控B亚基亚型B56δ的磷酸化，探索了心肌细胞中PP2A可能的β-肾上腺素能调控。磷酸亲和SDS-PAGE和免疫印迹分析显示，暴露于β-肾上腺素能受体（βAR）激动剂异丙肾上腺素（ISO）的成年大鼠心室肌细胞（ARVM） B56δ磷酸化增加。B56δ的磷酸化发生在S573，主要是通过刺激β1AR亚型，并依赖于PKA活性。用表达野生型（WT）或非磷酸化（S573A） B56δ的腺病毒转导ARVM，在n端与GFP融合，探讨了磷酸化的功能作用。在表达GFP-B56δ-WT或GFP-B56δ-S573A的ARVM中，C亚基表达增加，这两种亚基与内源性C和A亚基共同免疫沉淀。在表达GFP-B56δ-WT而非GFP-B56δ-S573A的ARVM中，细胞裂解物中PP2A活性随ISO的增加而增加。免疫印迹分析表达GFP-B56δ-WT或GFP-B56δ-S573A的ARVM中磷酸化蛋白质组，抗体检测(i)不同激酶底物基序中的磷酸化丝氨酸/苏氨酸残基，或（ii）选定蛋白中具有重要功能的特定磷酸化残基，结果显示，在没有或存在ISO刺激的情况下，磷酸化谱相似。在心肌细胞中，βAR刺激可诱导pka介导的PP2A调节亚基异构体B56δ在S573位点的磷酸化，从而增加相关的PP2A催化活性。这可能调节了特定B56δ-PP2A底物的磷酸化状态，具体的底物还有待鉴定。PP2A亚基B56δ在β-肾上腺素能刺激心肌细胞时磷酸化。磷酸化发生在Ser573位点，增加了B56δ-PP2A的催化活性。这种反应是由β1-肾上腺素能受体亚型和蛋白激酶a介导的。
Type 2A protein phosphatase (PP2A) enzymes are serine/threonine phosphatases which comprise a scaffold A subunit, a regulatory B subunit and a catalytic C subunit, and have been implicated in the dephosphorylation of multiple cardiac phosphoproteins. B subunits determine subcellular targeting, substrate specificity and catalytic activity, and can themselves be regulated by post-translational modifications. We explored potential β-adrenergic regulation of PP2A in cardiomyocytes through phosphorylation of the regulatory B subunit isoform B56δ. Phosphate affinity SDS-PAGE and immunoblot analysis revealed increased phosphorylation of B56δ in adult rat ventricular myocytes (ARVM) exposed to the β-adrenergic receptor (βAR) agonist isoprenaline (ISO). Phosphorylation of B56δ occurred at S573, primarily through stimulation of the β1AR subtype, and was dependent on PKA activity. The functional role of the phosphorylation was explored in ARVM transduced with adenoviruses expressing wild type (WT) or non-phosphorylatable (S573A) B56δ, fused to GFP at the N-terminus. C subunit expression was increased in ARVM expressing GFP-B56δ-WT or GFP-B56δ-S573A, both of which co-immunoprecipitated with endogenous C and A subunits. PP2A activity in cell lysates was increased in response to ISO in ARVM expressing GFP-B56δ-WT but not GFP-B56δ-S573A. Immunoblot analysis of the phosphoproteome in ARVM expressing GFP-B56δ-WT or GFP-B56δ-S573A with antibodies detecting (i) phospho-serine/threonine residues in distinct kinase substrate motifs or (ii) specific phosphorylated residues of functional importance in selected proteins revealed a comparable phosphorylation profile in the absence or presence of ISO stimulation. In cardiomyocytes, βAR stimulation induces PKA-mediated phosphorylation of the PP2A regulatory subunit isoform B56δ at S573, which increases associated PP2A catalytic activity. This is likely to regulate the phosphorylation status of specific B56δ-PP2A substrates, which remain to be identified. PP2A subunit B56δ is phosphorylated on β-adrenergic stimulation of cardiomyocytes. Phosphorylation occurs at Ser573 and increases B56δ-PP2A catalytic activity. Response is mediated by the β1-adrenoceptor subtype and protein kinase A. Phosphorylated B56δ abundance is increased in pathological cardiac hypertrophy.
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影响因子：
--
作者：
Flynn, Maxfield P.;Maizels, Evelyn T.;Hunzicker-Dunn, Mary
通讯作者：
Hunzicker-Dunn, Mary
影响因子：
4.8
作者：
El-Armouche, A;Rau, T;Eschenhagen, T
通讯作者：
Eschenhagen, T
影响因子：
5
作者：
Grimm M;Brown JH
通讯作者：
Brown JH
DOI：
10.1152/ajpheart.00059.2007
发表时间：
2007-07-01
影响因子：
4.8
作者：
Bhasin, Naina;Cunha, Shane R.;Mohler, Peter J.
通讯作者：
Mohler, Peter J.
影响因子：
4.8
作者：
DeGrande, Sean T.;Little, Sean C.;Mohler, Peter J.
通讯作者：
Mohler, Peter J.