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Science 335 (6069): 669-670

Copyright © 2012 by the American Association for the Advancement of Science

It's All in the Symmetry

Jeff Abramson, Aviv Paz, Kenneth D. Philipson

Calcium ion (Ca2+) signaling is essential to many cellular processes, from fertilization to apoptosis (cell death). Stable Ca2+ levels are achieved through tightly regulated and coordinated cellular processes. Alterations in Ca2+ levels are involved in many pathological conditions, including stroke and heart failure (1). After Ca2+ stimulation, the Na+/Ca2+ exchanger (NCX)—a ubiquitous Ca2+ export protein residing in the plasma membrane—participates in the restoration of resting levels of Ca2+ in excitable cells. On page 686 of this issue, Liao et al. (2) report the structure of a prokaryotic homolog of NCX, revealing a symmetrical protein scaffold and ion-binding pocket that provides detailed insights into the Na+/Ca2+ exchange process.

Department of Physiology and the Cardiovascular Research Laboratories, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.

E-mail: jabramson{at}

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