%ASong, Wei%AGottschalk, Carter%ATang, Tuo-Xian%ABiscardi, Andrew%AEllena, Jeffrey%AFinkielstein, Carla%ABrown, Anne%ACapelluto, Daniel%BJournal Name: Scientific Reports; Journal Volume: 10; Journal Issue: 1; Related Information: CHORUS Timestamp: 2021-08-10 19:53:52 %D2020%INature Publishing Group %JJournal Name: Scientific Reports; Journal Volume: 10; Journal Issue: 1; Related Information: CHORUS Timestamp: 2021-08-10 19:53:52 %K %MOSTI ID: 10182888 %PMedium: X %TStructural, in silico, and functional analysis of a Disabled-2-derived peptide for recognition of sulfatides %XAbstract

Disabled-2 (Dab2) is an adaptor protein that regulates the extent of platelet aggregation by two mechanisms. In the first mechanism, Dab2 intracellularly downregulates the integrin αIIbβ3receptor, converting it to a low affinity state for adhesion and aggregation processes. In the second mechanism, Dab2 is released extracellularly and interacts with the pro-aggregatory mediators, the integrin αIIbβ3receptor and sulfatides, blocking their association to fibrinogen and P-selectin, respectively. Our previous research indicated that a 35-amino acid region within Dab2, which we refer to as the sulfatide-binding peptide (SBP), contains two potential sulfatide-binding motifs represented by two consecutive polybasic regions. Using molecular docking, nuclear magnetic resonance, lipid-binding assays, and surface plasmon resonance, this work identifies the critical Dab2 residues within SBP that are responsible for sulfatide binding. Molecular docking suggested that a hydrophilic region, primarily mediated by R42, is responsible for interaction with the sulfatide headgroup, whereas the C-terminal polybasic region contributes to interactions with acyl chains. Furthermore, we demonstrated that, in Dab2 SBP, R42 significantly contributes to the inhibition of platelet P-selectin surface expression. The Dab2 SBP residues that interact with sulfatides resemble those described for sphingolipid-binding in other proteins, suggesting that sulfatide-binding proteins share common binding mechanisms.

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