ATP-enhanced molecular chaperone functions of the small heat shock protein human αB crystallin
- 3 February 1998
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 95 (3) , 1004-1009
- https://doi.org/10.1073/pnas.95.3.1004
Abstract
We report direct experimental evidence that human alphaB-crystallin, a member of the small heat shock protein family, actively participates in the refolding of citrate synthase (CS) in vitro. In the presence of 3.5 mM ATP, CS reactivation by alphaB-crystallin was enhanced approximately twofold. Similarly, 3.5 mM ATP enhanced the chaperone activity of alphaB-crystallin on the unfolding and aggregation of CS at 45 degrees C. Consistent with these findings, cell viability at 50 degrees C was improved nearly five orders of magnitude in Escherichia coli expressing alphaB-crystallin. SDS/PAGE analysis of cell lysates suggested that alphaB-crystallin protects cells against physiological stress in vivo by maintaining cytosolic proteins in their native and functional conformations. This report confirms the action of alphaB-crystallin as a molecular chaperone both in vitro and in vivo and describes the enhancement of alphaB-crystallin chaperone functions by ATP.Keywords
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