Insights That Move the GPCR Field Forward

Discovery programs rarely fail because a molecule “did nothing.” They fail because a molecule behaved exactly as the underlying system allowed—amplified, buffered, redirected, or reshaped by layers of receptor biology that weren’t accounted for. The October 30th AMA with Dr. Kenakin highlighted a fundamental truth: GPCR systems do not offer stable, proportional input–output relationships. Receptor density, constitutive activity, coupling efficiency, local signaling archit

In this foundational lesson, Terry Kenakin dives deep into a widely used, often misunderstood tool in early drug discovery: the calcium assay. Revered for its convenience, the FLIPR assay provides rapid insights into receptor activity. But its speed comes with a cost.