Binding of the concave surface of the Sds22 superhelix to the α4/α5/α6-triangle of protein phosphatase-1
Binding of the concave surface of the Sds22 superhelix to the α4/α5/α6-triangle of protein phosphatase-1
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DOI：
10.1074/jbc.m206838200
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发表时间：
2002-12-06
影响因子：
4.8
通讯作者：
Bollen, M
中科院分区：
文献类型：
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作者：
Ceulemans, H;Vulsteke, V;Bollen, M
对蛋白磷酸酶-1(PP1)调节因子Sds22的功能研究表明，它间接和/或直接参与了PP1最古老的功能之一，即通过极光相关的蛋白激酶逆转磷酸化。我们预测Sds22的保守部分折叠成一个弯曲的超螺旋，并证明在这个超螺旋的凹面上，八个残基(Asp(148)、Phe(170)、Glu(192)、Phe(214)、Asp(280)、Glu(300)、Trp(302)或Tyr(327)中的任何一个的丙氨酸突变都会阻碍与PP1的相互作用。此外，我们还发现所有哺乳动物中的PP1亚型都有可能与Sds22结合。与截短版本的PP1以及由PP1片段和酵母PP1样蛋白磷酸酶Ppz1组成的嵌合蛋白相互作用的研究表明，Sds22结合所需的位点(S)位于PP1Gamma(1)的第43和173个残基之间。在这个区域内，一个主要的相互作用位点被映射到由α4-、α5-和α6-螺旋描绘的三角形区域。我们的数据还表明，众所周知的PP1调节结合位点，如RVXF结合通道、Beta12/Beta13-环和酸性槽，对于与Sds22的相互作用并不是必需的。
Functional studies of the protein phosphatase-1 (PP1) regulator Sds22 suggest that it is indirectly and/or directly involved in one of the most ancient functions of PP1, i.e. reversing phosphorylation by the Aurora-related protein kinases. We predict that the conserved portion of Sds22 folds into a curved superhelix and demonstrate that mutation to alanine of any of eight residues (Asp(148), Phe(170), Glu(192), Phe(214), Asp(280), Glu(300), Trp(302), or Tyr(327)) at the concave surface of this superhelix thwarts the interaction with PP1. Furthermore we show that all mammalian isoforms of PP1 have the potential to bind Sds22. Interaction studies with truncated versions of PP1 and with chimeric proteins comprising fragments of PP1 and the yeast PP1-like protein phosphatase Ppz1 suggest that the site(s) required for the binding of Sds22 reside between residues 43 and 173 of PP1gamma(1). Within this region, a major interaction site was mapped to a triangular region delineated by the alpha4-, alpha5-, and alpha6-helices. Our data also show that well known regulatory binding sites of PP1, such as the RVXF-binding channel, the beta12/beta13-loop, and the acidic groove, are not essential for the interaction with Sds22.