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Purification of Hsp104, a Protein Disaggregase
Published on: September 30, 2011
The M-domain controls Hsp104 protein remodeling activity in an Hsp70/Hsp40-dependent manner
Bernhard Sielaff1, Francis T F Tsai
1Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Abstract:
Yeast Hsp104 is a ring-forming ATP-dependent protein disaggregase that, together with the cognate Hsp70 chaperone system, has the remarkable ability to rescue stress-damaged proteins from a previously aggregated state. Both upstream and downstream functions for the Hsp70 system have been reported, but it remains unclear how Hsp70/Hsp40 is coupled to Hsp104 protein remodeling activity. Hsp104 is a multidomain protein that possesses an N-terminal domain, an M-domain, and two tandem AAA(+) domains. The M-domain forms an 85-A long coiled coil and is a hallmark of the Hsp104 chaperone family. While the three-dimensional structure of Hsp104 has been determined, the function of the M-domain is unclear. Here, we demonstrate that the M-domain is essential for protein disaggregation, but dispensable for Hsp104 ATPase- and substrate-translocating activities. Remarkably, replacing the Hsp104 M-domain with that of bacterial ClpB, and vice versa, switches species specificity so that our chimeras now cooperate with the noncognate Hsp70/DnaK chaperone system. Our results demonstrate that the M-domain controls Hsp104 protein remodeling activities in an Hsp70/Hsp40-dependent manner, which is required to unleash Hsp104 protein disaggregating activity.
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