Structural pathway of regulated substrate transfer and threading through an Hsp100 disaggregase

Deville, Célia; Carroni, Marta; Franke, Kamila B.; Topf, Maya; Bukau, Bernd; Mogk, Axel; Saibil, Helen R.

doi:10.1126/sciadv.1701726

Cited by 124 publications

(212 citation statements)

References 41 publications

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“…Taken together, our findings imply that the NTD plays a regulatory role in the substrate remodeling activity of ClpB by firstly blocking the entrance to the pore loops so that harmful over‐potentiation of the machinery can be restricted and secondly acting as an additional anchor for rather large aggregates. Our proposed model of Mtb ClpB action correlates with recent studies on T. thermophilus and E. coli ClpB that support the regulatory role of the NTD in transferring substrate to the ClpB pore .…”

Section: Discussionsupporting

confidence: 85%

The amino‐terminal domain of Mycobacterium tuberculosis ClpB protein plays a crucial role in its substrate disaggregation activity

et al. 2018

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Mycobacterium tuberculosis ( Mtb ) is known to persist in extremely hostile environments within host macrophages. The ability to withstand such proteotoxic stress comes from its highly conserved molecular chaperone machinery. ClpB, a unique member of the AAA + family of chaperones, is responsible for resolving aggregates in Mtb and many other bacterial pathogens. Mtb produces two isoforms of ClpB, a full length and an N‐terminally truncated form (ClpB∆N), with the latter arising from an internal translation initiation site. It is not clear why this internal start site is conserved and what role the N‐terminal domain ( NTD ) of Mtb ClpB plays in its function. In the current study, we functionally characterized and compared the two isoforms of Mtb ClpB. We found the NTD to be dispensable for oligomerization, ATP ase activity and prevention of aggregation activity of ClpB. Both ClpB and ClpB∆N were found to be capable of resolubilizing protein aggregates. However, the efficiency of ClpB∆N at resolubilizing higher order aggregates was significantly lower than that of ClpB. Further, ClpB∆N exhibited reduced affinity for substrates as compared to ClpB. We also demonstrated that the surface of the NTD of Mtb ClpB has a hydrophobic groove that contains four hydrophobic residues: L97, L101, F140 and V141. These residues act as initial contacts for the substrate and are crucial for stable interaction between ClpB and highly aggregated substrates.

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Section: Discussionsupporting

confidence: 85%

The amino‐terminal domain of Mycobacterium tuberculosis ClpB protein plays a crucial role in its substrate disaggregation activity

et al. 2018

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“…This finding suggests that the mechanism of engagement of pore‐1 loops in these AAA + modules of LonA and ClpB might be indeed similar. Our observations, combined with the data derived from the structure of ClpB with bound substrate that designate the AAA + ‐2 module as being the main motor of ClpB, give a new perspective to a functional meaning of the resemblance between the sole ATPase module of class II and the AAA + ‐2 module of class I of the AAA + proteins, and also correlate with the matching topology between the HI(CC) domain of LonAs and H1 domain of ClpBs.…”

Section: Resultsmentioning

confidence: 59%

New insights into structural and functional relationships between LonA proteases and ClpB chaperones

et al. 2019

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LonA proteases and ClpB chaperones are key components of the protein quality control system in bacterial cells. LonA proteases form a unique family of ATPases associated with diverse cellular activities (AAA + ) proteins due to the presence of an unusual N‐terminal region comprised of two domains: a β‐structured N domain and an α‐helical domain, including the coiled‐coil fragment, which is referred to as HI(CC). The arrangement of helices in the HI(CC) domain is reminiscent of the structure of the H1 domain of the first AAA + module of ClpB chaperones. It has been hypothesized that LonA proteases with a single AAA + module may also contain a part of another AAA + module, the full version of which is present in ClpB. Here, we established and tested the structural basis of this hypothesis using the known crystal structures of various fragments of LonA proteases and ClpB chaperones, as well as the newly determined structure of the Escherichia coli LonA fragment (235–584). The similarities and differences in the corresponding domains of LonA proteases and ClpB chaperones were examined in structural terms. The results of our analysis, complemented by the finding of a singular match in the location of the most conserved axial pore‐1 loop between the LonA NB domain and the NB2 domain of ClpB, support our hypothesis that there is a structural and functional relationship between two coiled–coil fragments and implies a similar mechanism of engagement of the pore‐1 loops in the AAA + modules of LonAs and ClpBs.

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“…This generalized model is supported by conservation of pore loop residues and other key structural elements (Monroe & Hill 2016, Sauer & Baker 2011) and by a series of recent structures of other AAA+ ATPases in complex with mixed polypeptide substrates (Deville et al 2017, Gates et al 2017, Puchades et al 2017, Ripstein et al 2017). These structures collectively represent a long-awaited breakthrough in our understanding of this large and important class of cellular machines (Harrison 2004), whose well-known representatives include essential activities like the 19S proteasome, NSF, and p97/Cdc48.…”

Section: Vps4 and Related Aaa Atpasesmentioning

confidence: 85%

Structures, Functions, and Dynamics of ESCRT-III/Vps4 Membrane Remodeling and Fission Complexes

McCullough

Frost

Sundquist

2018

Annu. Rev. Cell Dev. Biol.

222

272

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The endosomal sorting complexes required for transport (ESCRT) pathway mediates cellular membrane remodeling and fission reactions. The pathway comprises five core complexes: ALIX, ESCRT-I, ESCRT-II, ESCRT-III, and Vps4. These soluble complexes are typically recruited to target membranes by site-specific adaptors that bind one or both of the early-acting ESCRT factors: ALIX and ESCRT-I/ESCRT-II. These factors, in turn, nucleate assembly of ESCRT-III subunits into membrane-bound filaments that recruit the AAA ATPase Vps4. Together, ESCRT-III filaments and Vps4 remodel and sever membranes. Here, we review recent advances in our understanding of the structures, activities, and mechanisms of the ESCRT-III and Vps4 machinery, including the first high-resolution structures of ESCRT-III filaments, the assembled Vps4 enzyme in complex with an ESCRT-III substrate, the discovery that ESCRT-III/Vps4 complexes can promote both inside-out and outside-in membrane fission reactions, and emerging mechanistic models for ESCRT-mediated membrane fission.

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Structural pathway of regulated substrate transfer and threading through an Hsp100 disaggregase

Abstract: Cryo-EM structures of ClpB complexes reveal a pathway for substrate transfer and translocation during protein disaggregation.

Cited by 124 publications

References 41 publications

The amino‐terminal domain of Mycobacterium tuberculosis ClpB protein plays a crucial role in its substrate disaggregation activity

The amino‐terminal domain of Mycobacterium tuberculosis ClpB protein plays a crucial role in its substrate disaggregation activity

New insights into structural and functional relationships between LonA proteases and ClpB chaperones

Structures, Functions, and Dynamics of ESCRT-III/Vps4 Membrane Remodeling and Fission Complexes

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