KRAS is a small GTPase in the RAS protein family that regulates key cellular processes such as proliferation, differentiation, and survival through the RAS-RAF signaling pathway. Activation of KRAS occurs when GDP is exchanged for GTP, enabling interaction with downstream effectors including cRAF. Mutations in KRAS are frequently associated with human cancers, making the KRAS-cRAF interaction an important target for therapeutic development. The KRAS (Q61R)-cRAF Binding Assay Kit is a TR-FRET–based assay designed to measure the interaction between activated KRAS and cRAF. In this assay, Tag2-KRAS (Q61R) is loaded with GppNHp to mimic the active GTP-bound state, while Tag1-cRAF RBD binds activated KRAS. Binding generates a FRET signal detected by fluorescence emission at 665 nm and 620 nm. Inhibitors that disrupt KRAS-cRAF binding reduce the HTRF signal intensity.