With no explanation, label text_A→text_B with either "NOT ENOUGH INFO", "REFUTES" or "SUPPORTS".
text_A: The receptor consists of the tracellular ligand-binding domain .
text_B: They have a heteromeric structure in that each subunit consists of the extracellular ligand-binding domain and a transmembrane domain where the transmembrane domain in turn includes four transmembrane alpha helices .
REFUTES.