Impact of Missense Mutation on Protein Function

A researcher is investigating a series of mutations in a gene that is known to be involved in pluripotency and differentiation in stem cells. They identify a specific mutation that causes a substitution of valine with isoleucine at a critical site within the protein encoded by this gene. The researcher hypothesizes that this missense mutation alters the protein's function, leading to perturbations in cellular signaling pathways. Considering the specific nature of this mutation, which aspect of protein function is most likely affected by such a substitution?