The findings are published in today's issue of Nature. "This
calcium transporter really is an important key to understanding
how the heart is regulated," said Dr. Donald Hilgemann,
professor of physiology and senior author of the study. "At
every beat, calcium in heart cells increases. And it's calcium
that is the messenger to the heart to get it to contract. "We
knew for a long time that NCX1 brings calcium into and out of
heart cells by exchanging it for sodium. And in doing so it
generates important electrical currents in the heart. The
surprise is that this transporter dances more than just that old
waltz from Vienna. It knows Salsa!" The research reveals two new
modes of operation of NCX1. First, the membrane protein can move
sodium into heart cells without moving calcium out. This mode
generates an electrical current independent of calcium transport
that contributes to excitation of the heart. The second mode is
to move calcium into heart cells without generating any
electrical current. This mode, Dr. H