Abstract
Calcineurin is an essential serine/threonine phosphatase that plays vital roles in neuronal development and function, heart growth, and immune system activation. Calcineurin is unique in that it is the only phosphatase known to be activated by calmodulin in response to increasing intracellular calcium concentrations. Calcium-loaded calmodulin binds to the regulatory domain of calcineurin, resulting in a conformational change that removes an autoinhibitory domain from the active site of the phosphatase. We have determined a 1.95 Å crystal structure of calmodulin bound to a peptide corresponding to its binding region from calcineurin. In contrast to previous structures of this complex, our structure has a stoichiometry of 1:1 and has the canonical collapsed, wraparound conformation observed for many calmodulin-substrate complexes. In addition, we have used size-exclusion chromatography and time-resolved fluorescence to probe the stoichiometry of binding of calmodulin to a construct corresponding to almost the entire regulatory domain from calcineurin, again finding a 1:1 complex. Taken in sum, our data strongly suggest that a single calmodulin protein is necessary and sufficient to bind to and activate each calcineurin enzyme.
Original language | English |
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Pages (from-to) | 5779-5790 |
Number of pages | 12 |
Journal | Biochemistry |
Volume | 53 |
Issue number | 36 |
DOIs | |
State | Published - Sep 16 2014 |
Bibliographical note
Publisher Copyright:© 2014 American Chemical Society.
Funding
Funders | Funder number |
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American Heart Association | 11PRE7020001 |
National Center for Research Resources | |
National Institutes of Health (NIH) | P20 RR020171 |
National Science Foundation (NSF) | MCB-0843551 |
National Science Foundation (NSF) | 1004931, 1358627 |
National Center for Research Resources | P20RR020171 |
ASJC Scopus subject areas
- Biochemistry