Candy Laura Steffen

Abstract Hyperactive Ras signalling is found in most cancers. Ras proteins are only active in membrane nanoclusters, which are therefore potential drug targets. We previously showed that the nanocluster scaffold galectin-1 (Gal1) enhances H-Ras nanoclustering via direct interaction with the Ras binding domain (RBD) of Raf. Here, we establish that the B-Raf preference of Gal1 emerges from the divergence of the Raf RBDs at their proposed Gal1-binding interface.

Abstract Bioluminescence resonance energy transfer (BRET) allows to quantitate protein interactions in intact cells. Here we provide a step-by-step protocol for measuring BRET due to transient interactions of oncogenic K-RasG12V in plasma membrane nanoclusters of HEK293-EBNA cells. We describe how to seed, transfect and replate cells, followed by their preparation for BRET-measurements on a microplate reader and detailed data analysis steps.

Abstract The Ras-MAPK pathway is critical to regulate cell proliferation and differentiation. Its dysregulation is implicated in the onset and progression of numerous types of cancers. To be active, Ras proteins are membrane anchored and organized into nanoclusters, which realize high-fidelity signal transmission across the plasma membrane. Nanoclusters therefore represent potential drug targets. However, targetable protein components of signalling nanoclusters are poorly established.