Structural evidence of a phosphoinositide-binding site in the Rgd1-RhoGAP domain

We report here the X-ray structure of the Rgd1p–RhoGAP domain, identify by NMR spectroscopy and confirm by docking simulations, a new but cryptic phosphoinositide-binding site, comprising contiguous A1, A1' and B helices. The addition of helix A1', unusual among RhoGAP domains, seems to be crucial for lipid interactions. Such a site was totally unexpected inside a RhoGAP domain, as it was not predicted from either the protein sequence or its three-dimensional structure. Phosphoinositide-binding sites in RhoGAP domains have been reported to correspond to polybasic regions, which are located at the unstructured flexible termini of proteins. Solid-state NMR spectroscopy experiments confirm the membrane interaction of the Rgd1p–RhoGAP domain upon the addition of PtdIns(4,5)P2 and indicate a slight membrane destabilization in the presence of the two partners.

Source: Biochemical Journal - September 20, 2017 Category: Biochemistry Authors: Martinez, D., Langlois d'Estaintot, B., Granier, T., Tolchard, J., Courreges, C., Prouzet-Mauleon, V., Hugues, M., Gallois, B., Doignon, F., Odaert, B. Tags: Research Articles Source Type: research