Analyze the Interaction Between Phostensin and EHD Proteins

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Four types of EHD proteins, including EHD1, EHD2, EHD3 and EHD4, have been identified in mammalian cells. All EHD proteins have been implicated in the regulation of endocytic transport. EHD proteins contain four recognizable domains from the N-terminus to C-terminus: an N-terminal helical domain (NT), an ATP-binding domain (G domain), a central coiled-coil region and a C-terminal EH domain. Phostensin (protein phosphatase1 F-actin cytoskeleton targeting subunit), encoded by KIAA1949, is a protein phosphatase 1 (PP1)-binding protein. The previous study in our lab has demonstrated that phostensin is an EHD-binding protein. Most of the EHD-binding proteins contain an Asp-Pro-Phe (NPF) motif that interacts with EH-domain of EHD proteins. However, phostensin lacks the NPF motif. It remained unknown how phostensin interacts with EHD proteins. In my study, I demonstrated that residues 60-80 of phostensin interact with the G-domain of EHD1 (or EHD4).