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OperonBiology
Put in orderDifficulty 2/5 · StandardConcept explanationVisual representation

From adrenaline to glucose

Topic: Signal transduction

In the 1950s Earl Sutherland's group studied how adrenaline (epinephrine) makes liver cells break down glycogen. Working with broken liver cells, they found that the hormone acted on the membrane fraction, which then produced a small, heat-stable molecule, later identified as cyclic AMP, that switched on glycogen breakdown in the soluble fraction. The steps below follow this cAMP route, starting from a β-adrenergic receptor, a G protein-coupled receptor.

Put the events in the order they happen in the liver cell, from the hormone arriving to glycogen being broken down.

Drag the items, or use the arrow buttons, so the first event is at the top.

  1. 1cAMP binds protein kinase A (PKA) and activates it.
  2. 2The α subunit of the G protein Gs releases GDP and binds GTP.
  3. 3Glycogen phosphorylase splits glucose-1-phosphate units off glycogen.
  4. 4Adrenaline binds the β-adrenergic receptor on the outside of the plasma membrane.
  5. 5PKA phosphorylates phosphorylase kinase, switching it on.
  6. 6Adenylyl cyclase converts ATP into cAMP.
  7. 7Phosphorylase kinase phosphorylates glycogen phosphorylase, switching it on.

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