Lipid Cooperativity as a General Membrane-Recruitment Principle for PH Domains

•The lipid-binding properties of 91 pleckstrin homology domains have been quantified•Over 10,000 individual protein-lipid interaction experiments have been performed•The binding specificity and affinity imply cooperativity between signaling lipids•Mutations found in cancer biopsies fine-tune lipid-binding specificities

SummaryMany cellular processes involve the recruitment of proteins to specific membranes, which are decorated with distinctive lipids that act as docking sites. The phosphoinositides form signaling hubs, and we examine mechanisms underlying recruitment. We applied a physiological, quantitative, liposome microarray-based assay to measure the membrane-binding properties of 91 pleckstrin homology (PH) domains, the most common phosphoinositide-binding target. 10,514 experiments quantified the role of phosphoinositides in membrane recruitment. For most domains examined, the observed binding specificity implied cooperativity with additional signaling lipids. Analyses of PH domains with similar lipid-binding profiles identified a conserved motif, mutations in which—including some found in human cancers—induced discrete changes in binding affinities in vitro and protein mislocalization in vivo. The data set reveals cooperativity as a key mechanism for membrane recruitment and, by enabling the interpretation of disease-associated mutations, suggests avenues for the design of small molecules targeting PH domains.

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