Thapsigargin is a tightly-binding inhibitor of a class of enzymes known by the acronym SERCA, which stands for sarco / endoplasmic reticulum Ca 2+ ATPase. Structurally, thapsigargin is classified as a sesquiterpene lactone, and is extracted from a plant, Thapsia Garganica. It is a tumor promoter in mammalian cells, though, and is also the target of the newer artemesinin derived anti-malarial drugs.

Thapsigargin raises cytosolic calcium concentration by (1) blocking the ability of the cell to pump calcium out, (2) opening IP3-gated channels in the endoplasmic reticulum (ER), and (3) activating plasma membrane calcium channels, allowing an influx of calcium to the cytosol.

Thapsigargin, along with ATP, is useful in experimentation examining the impacts of increasing cytosolic calcium concentrations. Such compounds are known as calcium agonists due to their ability to increase cellular concentrations of calcium.

External links

Vendors' product pages about thapsigargin:

• GMP/API grade Thapsigargin from Fermentek.
• Thapsigargin by AG Scientific, Biochemical Manufacturer

Potential medical uses of Thapsigargin

Thapsigagrin is mentioned as a possible treatment for cataract.

• Nat Med. 1997 Sep;3(9):1026-8,
  Thapsigargin-coated intraocular lenses inhibit human lens cell growth
• Ibaraki N., Nat Med. 1997 Sep;3(9):958-60. A brighter future for cataract surgery.