The GRP1 (general receptor for phosphoinositide) protein binds phosphatidylinositol-3,4,5-triphosphate (PIP3) through a pleckstrin homology domain and displays a region of high sequence similarity to the yeast Sec7 protein.
Figure 1: PIP3 Binding to GRP-PH. Biotinylated PI(3,4,5)P3 or PI(4,5)P2 was added to a GRP-PH coated 96-well plate. After a one hour incubation, the plate was washed and blocked with 1X PBS / 1% BSA. The capture phosphoinositol was detected with Streptavidin-HRP and TMB substrate.