Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery: Bridging Experiments and Computations - September 10-14, 2014, Istanbul, Turkey

Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery Poster Session II

80-POS Board 33 The Last 10 Residues of Human Sphingosine-1-Phosphate Receptor 1 Interacts with G- Protein Coupled Receptor Kinases in A Conserved Manner Emel Sen 1 , Yusuf Dogus Dogru 1 , Ozlem Keskin 1 , Attila Gursoy 1 , Kumlesh K. Dev 2 . 1 Koc University, Istanbul, Turkey, 2 Trinity College Dublin, Dublin, Ireland. Sphingosine-1-phosphate receptors are a family of G-protein coupled receptors (GPCRs) highly expressed in human cells. They have roles in cellular proliferation, survival and migration. Similar to other GPCRs, Sphingosine-1-phosphate receptor 1 (S1PR1) C-terminal internalization via phosphorylation is an important intracellular mechanism for the downstream signaling. To better understand S1PR1 pathways, we synthesized a peptide consisting of the last 10 residues of the C-terminal of S1PR1, which we termed MNP301. We experimentally showed that MNP301 prevents S1PR1 internalization and uncouples the agonistic effect of phosphorylated FTY720, a modulator of S1PR1. However, how these last 10 residues prevent S1PR1 redistribution is still unclear. Several studies show that G-protein coupled receptor kinases (GRKs) are involved in the S1PR1 internalization and C-terminal phosphorylation. In this study, we investigated the specific interactions of these last 10 residues and GRKs by using three different docking tools. Our analysis shows that all GRKs available in Protein Data Bank (GRK1, GRK2, GRK3 and GRK6) bind to MNP301 from the same binding pocket with similar energy values. Our in silico results suggest that the peptide binds to GRKs in between their N-terminal regulator of G-protein signaling (RGS) domain and protein kinase domain. We will further use Molecular Dynamics (MD) and Perturbation Response Scanning (PRS) tools to give insight into the binding mechanism and allosteric residues of GRKs. A deeper comprehension of these interactions will contribute a better understanding of S1PR1 signaling pathways.

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