Lee Eunhee, Stafford Walter F
Cardiovascular Biology Program and AUC Research Laboratory, Boston Biomedical Research Institute, 64 Grove St, Watertown, MA, 02472, United States of America.
PLoS One. 2015 Oct 7;10(10):e0139875. doi: 10.1371/journal.pone.0139875. eCollection 2015.
Scaffold proteins bind to and functionally link protein members of signaling pathways. Interaction of the scaffold proteins, myosin phosphatase target subunit (MYPT1) and myosin phosphatase-RhoA interacting protein (MRIP), causes co-localization of myosin phosphatase and RhoA to actomyosin. To examine biophysical properties of interaction of MYPT1 with MRIP, we employed analytical ultracentrifugation and surface plasmon resonance. In regard to MRIP, its residues 724-837 are sufficient for the MYPT1/MRIP interaction. Moreover, MRIP binds to MYPT1 as either a monomer or a dimer. With respect to MYPT1, its leucine repeat region, LR (residues 991-1030) is sufficient to account for the MYPT1/MRIP interaction. Furthermore, point mutations that replace glutamic acids 998-1000 within LR reduced the binding affinity toward MRIP. This suggests that the glutamic acids of MYPT1 play an important role in the interaction.
支架蛋白与信号通路中的蛋白质成员结合并在功能上连接它们。支架蛋白肌球蛋白磷酸酶靶向亚基（MYPT1）和肌球蛋白磷酸酶-RhoA相互作用蛋白（MRIP）之间的相互作用，导致肌球蛋白磷酸酶和RhoA共定位于肌动球蛋白。为了研究MYPT1与MRIP相互作用的生物物理特性，我们采用了分析超速离心和表面等离子体共振技术。就MRIP而言，其724-837位残基足以实现MYPT1/MRIP的相互作用。此外，MRIP以单体或二聚体的形式与MYPT1结合。就MYPT1而言，其亮氨酸重复区域LR（991-1030位残基）足以解释MYPT1/MRIP的相互作用。此外，取代LR内998-1000位谷氨酸的点突变降低了对MRIP的结合亲和力。这表明MYPT1的谷氨酸在相互作用中起重要作用。
