RT Journal Article
SR Electronic
T1 Unique unfoldase/aggregase activity of a molecular chaperone that dysregulates a translational elongation factor
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 492876
DO 10.1101/492876
A1 Ku-Sung Jo
A1 Ji-Hun Kim
A1 Kyoung-Seok Ryu
A1 Young-Ho Lee
A1 Che-Yeon Wang
A1 Joo-Seong Kang
A1 Yoo-Sup Lee
A1 Min-Duk Seo
A1 Hyung-Sik Won
YR 2018
UL http://biorxiv.org/content/early/2018/12/10/492876.abstract
AB The various chaperone activities of heat shock proteins contribute to ensuring cellular proteostasis. Here, we demonstrate the non-canonical unfoldase activity as an inherent functionality of the prokaryotic molecular chaperone Hsp33. The holding-inactive, reduced form of Hsp33 (RHsp33) strongly bound to the translational elongation factor, EF-Tu, and catalyzed the EF-Tu aggregation via evoking its aberrant folding, resulting in its susceptibility to proteolytic degradation by Lon. This interaction was critically mediated by the redox-switch domain of RHsp33 and the guanine nucleotide-binding domain of EF-Tu. The RHsp33-induced in vivo aggregation of EF-Tu upon heat shock was evident in a Lon-deficient strain and inhibited cell growth. Unlike wild-type Escherichia coli, the strain lacking both Hsp33 and Lon showed a non-reduced level of EF-Tu and diminished capability of counteracting heat shock. These findings suggest that the unique unfoldase/aggregase activity of Hsp33 potentially involved in protein turnover confers a cellular survival advantage under heat-stressed conditions.