Understanding how calcium works at the molecular level is one of the keys to understanding human immune response. Scientists know that calcium controls the growth and development of cells. But no one is really sure what controls it. Until now, that is. It's taken six years, but York doctoral candidate in biology John Moniakis seems to have identified some parts of the puzzle.

    Scientists have been finding new clues to that mystery, and Moniakis, working in the lab of York biology professor Barrie Coukell, has added some of his own.

    It's now known that calcium triggers an enzyme called calcineurin ? an important component of the human immune system. Calcineurin in turn activates the different genes which control aspects of immune response and cell growth.

    Moniakis worked with an amoebae called Dictyostelium discoideum, a simple organism whose developing Dictyostelium cells are similar, in very basic ways, to developing human embryos. He found calcium controls a gene which makes a protein (PAT1) which, in a loop, controls the calcium.

    "I've shown that PAT1 regulates calcium concentrations in the cell," he says. He notes that this is "a crucial function because when levels of calcium inside the cells become too high, the calcium can switch on signals which alter cellular function that shouldn't be turned on, and dangerous complications can arise."

    Moniakis found that when calcium levels became too high in Dictyostelium cells calcineurin was turned on. That caused PAT1 to be synthesized which in turn lowered the calcium levels back to normal by "expelling" it or transporting it into an organelle within the cell called the contractile vacuole. He says his lab is working on understanding the pathway that calcineurin uses to regulate levels of PAT1 and possibly other proteins as well.

Painting: Eric Mohr