Modulation of Homer1 EVH1 domain internal dynamics by putative autism-associated mutations

The EVH1 domain of the Homer1 scaffold protein interacts with the proline-rich region of Shank3, forming a key network within the postsynaptic density. While two mutations (M65I and S97L) in the EVH1 domain have been suggested to be associated with autism spectrum disorder, our results show that neither mutation has a substantial effect on the overall structure or the partner binding properties of Homer1. Compared to the S97L variant, the M65I mutant exhibits larger chemical shift perturbations both upon the mutation itself and during partner binding, while also showing signs of thermal destabilization. Finally, integration of computational and NMR data suggests that both mutations perturb the μs-ms timescale internal motions of the EVH1 domain.