Detecting Low‐Affinity Extracellular Protein Interactions Using Protein Microarrays

Abstract

Low-affinity extracellular protein interactions are critical for cellular recognition processes, but are not generally detected by methods that can be applied in a high-throughput manner. This unit describes a protein microarray platform that significantly improves the throughput of assays capable of detecting transient extracellular protein interactions. These methodological improvements now permit screening for novel extracellular receptor-ligand interactions on a genome-wide scale.

Galectin‐9 activates platelet ITAM receptors glycoprotein VI and C‐type lectin‐like receptor‐2

“…To identify potential counter‐receptors of Gal‐9 on human platelets, we used the Avidity‐based Extracellular Interaction Screening Assay, 48 and found the platelet collagen receptor GPVI as a significant binding partner of Gal‐9 in vitro (Figure S5 in supporting information). Gal‐9 competitively inhibited the binding of recombinant dimeric GPVI‐Fc (25 nM) to a Horm collagen (10 nM)–coated surface in the solid‐phase binding assay, with an approximate IC 50 of 220 nM (Figure 4Ai), suggesting that the Gal‐9 binding site may overlap with the collagen binding site found within D1.…”