Prion protein interaction with the C-terminal SH3 domain of Grb2 studied using NMR and optical spectroscopy.
Transmissible spongiform encephalopathies have been observed exclusively in organisms expressing the host-encoded prion protein (PrP). The function of the cellular isoform of PrP found in healthy organisms has so far not been identified, although there are indications of a role in signal transduction in neurons. To gain further insight into the functional properties of cellular PrP, this paper investigated the binding of the C-terminal SH3 domain of the murine growth factor receptor-bound protein 2 (Grb2) to the murine PrP, using NMR, fluorescence, and circular dichroism spectroscopy. The SH3-binding site in murine PrP was thus found to be in the highly conserved region of residues 100-109, which contains prolines in positions 101 and 104. The protein-protein interaction, with a K(D) value of 5.5 microM, is abolished when either of these two prolines is replaced by leucine. In humans, two corresponding Pro --> Leu exchanges are found in patients who present with the Gerstmann-Sträussler-Scheinker syndrome. The results of the present study thus indicate a possible mechanism by which amino acid exchanges could influence a specific protein-protein interaction in a complex signal transduction cascade, which might be of functional significance in health and disease.
Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland.
Dominikus A
DA
Lysek
Kurt
K
Wüthrich
D048868:Adaptor Proteins, Signal Transducing; D019943:Amino Acid Substitution / Q000235:genetics*; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D051380:GRB2 Adaptor Protein; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008958:Models, Molecular; D018621:PrPC Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495949:Grb2 protein, mouse; D018621:PrPC Proteins; D011506:Proteins