Interaction of Myosin Phosphatase Target Subunit (MYPT1) with Myosin Phosphatase-RhoA Interacting Protein (MRIP): A Role of Glutamic Acids in the Interaction

• Published in: PloS one Vol. 10; no. 10; p. e0139875
• Main Authors: Lee, Eunhee, Stafford, 3rd, Walter F
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 2015; Public Library of Science (PLoS)
• Subjects: Acids; Actomyosin; Biomedical research; Cell cycle; Dimerization; Experiments; Glutamic Acid - metabolism; GTP-Binding Proteins - metabolism; GTPase-Activating Proteins - metabolism; Humans; Hypertension; Kinases; Laboratories; Leucine; Light; Localization; Mutation; Myosin; Myosin-Light-Chain Phosphatase - metabolism; Peptides; Phosphatase; Protein Binding; Protein Interaction Domains and Motifs; Proteins; Recombinant Proteins; Residues; RhoA protein; Scaffolds; Sedimentation & deposition; Smooth muscle; Surface Plasmon Resonance; Ultracentrifugation; Velocity; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0139875

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.