A New Twist in the Transmembrane Signaling Tool-Kit

In this issue, Schlessinger and his colleagues () describe crystal structures of the complete extracellular region of the Kit receptor tyrosine kinase, both alone and in complex with its activating ligand, stem cell factor (SCF). The structures explain how SCF drives dimerization of the receptor. They also reveal important receptor-receptor contacts that may explain how several Kit mutations lead to cancer.