Defining A-Kinase Anchoring Protein (AKAP) Specificity for the Protein KinaseA Subunit RI (PKA-RI)
Defining A-Kinase Anchoring Protein (AKAP) Specificity for the Protein KinaseA Subunit RI (PKA-RI)
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DOI：
10.1002/cbic.201500632
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发表时间：
2016-04-15
期刊：
影响因子：
3.2
通讯作者：
Kennedy, Eileen J.
中科院分区：
文献类型：
--
作者：
Autenrieth, Karolin;Bendzunas, N. George;Kennedy, Eileen J.
A-激酶锚定蛋白（AKAP）是蛋白激酶A（PKA）的时空调节因子，它将PKA沿着于多种蛋白质中形成离散的信号复合物。AKAP通过α-螺旋与PKA全酶相互作用，所述α-螺旋以同种型依赖性方式对接到PKA-R的二聚化/对接结构域上形成的沟中。为了在分子水平上理解异构体选择性，设计了蛋白质-蛋白质相互作用（PPI）破坏物库，以系统地探测AKAP对接序列上的芳香残基对于RI选择性的意义。基于AKAP结合的高亲和力、RI选择性破坏剂RI-STAD-2设计钉合肽文库。发现Phe、Trp和Leu均保持RI选择性，而在该位置处的多个中等大小的疏水取代导致同种型选择性的丧失（Ile）或选择性的逆转（瓦尔）。由于目前已知的RI选择性序列数量有限，因此本研究有助于我们理解亚型选择性并建立用于发现其他RI选择性AKAP的参数。
A-Kinase anchoring proteins (AKAPs) act as spatial and temporal regulators of protein kinaseA (PKA) by localizing PKA along with multiple proteins into discrete signaling complexes. AKAPs interact with the PKA holoenzyme through an alpha-helix that docks into a groove formed on the dimerization/docking domain of PKA-R in an isoform-dependent fashion. In an effort to understand isoform selectivity at the molecular level, a library of protein-protein interaction (PPI) disruptors was designed to systematically probe the significance of an aromatic residue on the AKAP docking sequence for RI selectivity. The stapled peptide library was designed based on a high affinity, RI-selective disruptor of AKAP binding, RI-STAD-2. Phe, Trp and Leu were all found to maintain RI selectivity, whereas multiple intermediate-sized hydrophobic substitutions at this position either resulted in loss of isoform selectivity (Ile) or a reversal of selectivity (Val). As a limited number of RI-selective sequences are currently known, this study aids in our understanding of isoform selectivity and establishing parameters for discovering additional RI-selective AKAPs.