Calcium Homeostasis and Acidocalcisomes in Trypanosoma cruzi

Calcium ion (Ca2+) is an important second messenger in Trypanosoma cruzi and is essential for invasion of host cells by this parasite. A number of transporters and channels in the plasma membrane, endoplasmic reticulum, and mitochondria regulate cytosolic calcium concentration. Additionally, the T. cruzi genome contains a wide variety of signaling and regulatory proteins that bind calcium as well as many putative calcium-binding proteins that await further characterization. In T. cruzi, acidic organelles known as acidocalcisomes are the primary reservoir of intracellular calcium and mediate polyphosphate metabolism, osmoregulation, and calcium and pH homeostasis.