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bioRxiv · 10.1101/2021.05.27.445944

A distributed residue network permits conformational binding specificity in a conserved family of actin remodelers

Hwang, T.·Grant, R. A.·Keating, A. E.
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Abstract

Metazoan proteomes contain many paralogous proteins that have evolved distinct functions. The Ena/VASP family of actin regulators consists of three members that share an EVH1 interaction domain with a 100% conserved binding site. A proteome-wide screen revealed ciliary protein PCARE as a high-affinity ligand for ENAH EVH1. Here we report the surprising observation that PCARE is ~100-fold specific for ENAH over paralogs VASP and EVL and can selectively bind and inhibit ENAH-dependent adhesion in cells. Specificity arises from a mechanism whereby PCARE stabilizes a conformation of the ENAH EVH1 domain that is inaccessible to family members VASP and EVL. Structure-based modeling rapidly identified seven residues distributed throughout EVL that are sufficient to differentiate binding by ENAH vs. EVL. By exploiting the ENAH-specific conformation, we rationally designed the tightest and most selective ENAH binder to date. Our work uncovers a conformational mechanism of interaction specificity that distinguishes highly similar paralogs and establishes tools for dissecting specific Ena/VASP functions in processes including cancer cell invasion.

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Hwang, T., Grant, R. A., Keating, A. E.. 2021-05-27. A distributed residue network permits conformational binding specificity in a conserved family of actin remodelers. https://doi.org/10.1101/2021.05.27.445944

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