How Peptides Signal

The receptor family Kobilka won a Nobel for — and why ~1 in 3 drugs targets it

Peptides mostly talk to receptors

Most signaling peptides work by fitting a specific receptor — like a key cut for one lock. The single most important receptor family for peptide drugs is the G-protein-coupled receptor (GPCR). GPCRs are the target of an estimated one-third of all approved drugs.¹

Why Kobilka's Nobel matters

For decades GPCRs were understood only indirectly. Brian Kobilka (Stanford) captured the first high-resolution structures of a GPCR — including the receptor caught in the act of signaling — earning the 2012 Nobel Prize in Chemistry.¹ Seeing the actual shape is what lets chemists design molecules that fit.

Agonist vs antagonist

• An agonist binds and activates the receptor (semaglutide is a GLP-1 receptor agonist).
• An antagonist binds and blocks it.

"Partial" and "biased" agonists activate only some of a receptor's downstream signals — an active frontier in making drugs with fewer side effects.

The receptors behind this whole field

Further reading — primary sources

1. Kobilka — GPCR structure (2012 Nobel lecture / review). Angew. Chem. Int. Ed.
2. GPCRs & drug discovery — Stanford news. news.stanford.edu

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