Abstract
Abstract ID 26074
Poster Board 481
Nanobodies are small antibody-derived proteins suited for recognizing structural motifs and surface facets of target proteins with high specificity. Unlike their larger antibody counterparts, nanobodies can also access protein cavities normally accessible only to ligands or unique protein interaction partners. With such abilities, nanobodies have garnered much attention in G protein-coupled receptor (GPCR) research, as these receptors contain both extracellular- and intracellular-facing cavities for accommodating ligands and G proteins, respectively. Most efforts in GPCR nanobody development have focused on identifying those that stabilize defined receptor conformations for solving GPCR structures. That said, using these same approaches for identifying nanobodies that directly modulate receptor function has been a major challenge. Here, we present a new cell-based nanobody discovery platform specially designed for identifying functionally relevant GPCR nanobodies. In the engineered system, nanobody-receptor interactions are reported only when receptor function is influenced. Additionally, the interface at which nanobody-GPCR interactions occur can be finely controlled, enabling user-defined discovery of nanobodies that interact at/near the receptor’s ligand- or G protein-binding site. To date, we have demonstrated the platform’s ability to identify both extracellular- and intracellular-binding nanobodies and have shown both negative and positive modes of GPCR modulation. We are currently using the designed platform to identify similar nanobodies for over 30 unique GPCRs. We anticipate these efforts will yield a large panel of nanobodies for further exploring and enhancing structural, cellular, and pharmacological studies of GPCRs, providing valuable research tools and therapeutic candidates for basic and translational research alike.
This work was supported by NIH/NIGMS R35GM119518 to D.G.I.