Revealing the Structural Basis for Calprotectin-RAGE Signaling Axis

Faculty #13
Discipline: Chemistry and Chemical Sciences
Subcategory: STEM Research

Steven Damo - Fisk University

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The receptor for advanced glycation end products (RAGE) is a multiligand receptor that plays a central role in the immune system. RAGE has three extracellular domains, V, C1, and C2, a single helix transmembrane domain, and a short intracellular C-terminus that is largely unstructured. Despite its importance in signal transduction, little is known about the molecular mechanism of RAGE activation. Her hypothesis is that the calcium binding S100 protein family member calprotectin (CP) binds to the extracellular V domain of RAGE which results in in an activated oligomer that is stabilized by the C1 domain of distinct RAGE molecules.

Here we present a multidisciplinary approach combining computational, biophysical and biochemical methods toward understanding the molecular basis of RAGE activation. Computational docking studies of the CP-RAGE (VC1) complex have generated a model that reveals a critical basic and hydrophobic patch of the V domain surface. Mutation of a single residue in this patch lowers the binding affinity of RAGE for CP and related S100 ligands by five fold relative to WT RAGE (VC1). Additionally, using a fluorescence based assay we have demonstrated that the binding affinity of RAGE (V) and RAGE (VC1) for S100 proteins is the same. This suggests that ligand recognition by RAGE occurs only at the V domain. In total, these experiments represent important first steps toward characterizing the molecular mechanism of RAGE activation. Ongoing experiments are focused on characterizing the oligomerization state of various S100-RAGE (VC1) complexes as well as crystallization of the CP-RAGE complex to determine the high resolution structure.

Funder Acknowledgement(s): NSF HRD1400969

Faculty Advisor: None Listed,