{"knowledge_schema": {"broad_category": "Biochemistry \u2192 Protein Interactions \u2192 Post-Translational Modifications", "refinement": "This problem focuses on understanding the effects of phosphorylation on protein-protein interactions and the structural forms of proteins (monomers vs. dimers).", "specific_scope": "The context involves analyzing the results of SEC-MALS experiments to infer the interactions and affinities between different mammalian proteins under various conditions, including phosphorylation and dephosphorylation.", "goal": "Determine the correct statement regarding the effects of phosphorylation on protein A and its interactions with other proteins based on experimental data."}, "summary": "This problem involves analyzing protein-protein interactions and the impact of phosphorylation on these interactions. The experiments conducted with SEC-MALS provide insights into the masses of proteins and their complexes, allowing us to infer how phosphorylation affects their affinities. The goal is to identify the correct statement regarding the behavior of protein A in relation to its phosphorylation state and its interactions with other proteins. The answer indicates that phosphorylation of protein A decreases its affinity for other proteins and that protein A exists as a homodimer."}