Calcium a regulates proliferation: the functional role of voltage gated calcium channels in human lens epithelial cells. Calcium, as an integral part of a large number of cellular regulatory pathways, is selective in the control of specific cell functions like the start of G1 phase in cell cycle. Cell proliferation has been suggested to depend on increasing intracellular calcium levels. A major regulatory pathway for intracellular calcium is the calcium influx into the cell via voltage gated calcium channels. L- und T- Typ Cav regulate various cellular events, their expression seems to change during different biological events. Both Cav- types are expressed in human lens epithelial cells. Proliferation and migration of lens epithelial cells are the main causes of PCO, the most common complication of cataract surgery. Here, the hypothesis was tested if calcium influx via Cav channels regulates proliferation in these cells. We showed a proliferation- dependent expression of T- type Cavs. Furthermore, a blockade of Cav leads to the inhibition of cellular growth and the induction of apoptosis. These processes were mediated by the intracellular calcium and the activation of CaMKII, Raf-1 and ERK1/2.