Importance of N- and C-terminal Regions of IbpA, Escherichia coli Small Heat Shock Protein, for Chaperone Function and Oligomerization

Stróżecka, Joanna; Chruściel, Elżbieta; Górna, Emilia; Szymańska, Aneta; Ziętkiewicz, Szymon; Liberek, Krzysztof

doi:10.1074/jbc.m111.273847

Cited by 47 publications

(39 citation statements)

References 36 publications

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“…Both the NTR and ACD play an important role in the formation of oligomeric assemblies of these sHsps [1,3]. Apart from these two regions, the CTR also plays an important role in the structure, stability and chaperone function of sHsps [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The C‐terminal extension of Mycobacterium tuberculosis Hsp16.3 regulates its oligomerization, subunit exchange dynamics and chaperone function

et al. 2017

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Mycobacterium tuberculosis is a human pathogen that secretes a major immunodominant antigen, namely Hsp16.3, throughout the course of infection. Hsp16.3 belongs to the small heat shock protein family and exhibits a molecular chaperone function that is important for the growth and survival of M. tuberculosis in host cell macrophages. The importance of the N-terminal region for the structure and chaperone function of Hsp16.3 is well understood. However, the effect of the C-terminal region on these properties is far from clear. Therefore, we cloned, over-expressed and purified wild-type and seven C-terminal-truncated mutant proteins of Hsp16.3. Mutants with deletions of one and two C-terminal extension (CTE) residues had a structure and chaperone function similar to wild-type protein. Intriguingly, deletion of three residues from the CTE triggered perturbation of the tertiary structure, dissociation of the oligomeric assembly (dodecamer to octamer and dimer), enhancement of subunit exchange dynamics and improvement in the chaperone function of Hsp16.3. Interestingly, these structural modulations (except oligomeric dissociation) as well as chaperoning strength reached their apex upon truncation of the entire CTE ( RSTN ). Further deletions from the C-terminal region beyond the CTE increased only the degree of oligomeric dissociation, and the complete removal of this region made the protein into a dimer. Overall, our study suggests a 'new structural element' in the C-terminal region, i.e. the C-terminal extension, which plays an important role in the oligomerization, subunit exchange dynamics and chaperone function of Hsp16.3.

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Section: Introductionmentioning

confidence: 99%

The C‐terminal extension of Mycobacterium tuberculosis Hsp16.3 regulates its oligomerization, subunit exchange dynamics and chaperone function

et al. 2017

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“…In contrast to conventional in vitro studies (e.g. truncation of sHSPs) of our own (15,25,26) and of others (16,18,19,33,34), the in vivo photo-cross-linking approach apparently has such advantages as causing minimal structural disturbances on IbpB and facilitating analysis of the participation of individual residues of IbpB in binding natural substrate proteins in E. coli. Notably, Bpa-mediated in vitro photo-cross-linking was applied recently to determine the substrate-binding residues of Hsp18.1, a pea sHSP (17).…”

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confidence: 97%

“…Numerous in vitro studies indicate that the structurally disordered N-terminal arm of sHSPs is essential for sHSPs to bind model substrate proteins, although the ␣-crystallin domain and C-terminal extension might also be involved (15)(16)(17)(18)(19), and that their in vitro chaperone activities are enhanced upon exposure to heat shock conditions (13, 20 -22). Significant but unresolved scientific questions regarding the functions of sHSPs in living cells include which residues of sHSPs mediate the binding of the wide spectrum of natural substrate proteins (17) and how they play a role in the normally observed (although under in vitro conditions) heat shock-enhanced substrate-binding capacity of sHSPs (23).…”

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confidence: 99%

Small Heat Shock Protein IbpB Acts as a Robust Chaperone in Living Cells by Hierarchically Activating Its Multi-type Substrate-binding Residues

Shi

Yin

et al. 2013

Journal of Biological Chemistry

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Background: Small heat shock proteins are ubiquitous molecular chaperones. Results: A total of 20 and 48 substrate-binding residues in IbpB were identified to function at 30 and 50°C, respectively, in living cells. Conclusion:The substrate-binding residues of IbpB are hierarchically activated in a temperature-dependent manner. Significance: This is the first systematic identification of substrate-binding residues of a small heat shock protein in living cells.

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“…Studies by truncation or by chemical crosslinking showed that the three characteristic domains of sHSPs are all crucial for the chaperone functional integrity (Merck et al 1993b ;Fu and Chang 2006a ;Fu et al 2005 ;Leroux et al 1997b ;Jiao et al 2005b ;Lentze et al 2003 ;Saji et al 2008 ;Strozecka et al 2012 ;Studer et al 2002 ;Treweek et al 2007 ;Fu and Chang 2006b ;Lambert et al 2013 ;. However, these studies cannot reveal the exact role of each amino acid residue for substrate-binding.…”

Section: Structural Diversity and Spatial Chaos Of Substrate-binding mentioning

confidence: 99%

The Big Book on Small Heat Shock Proteins

Hightower¹,

Tanguay²

2015

Heat Shock Proteins

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Heat Shock Proteins: key mediators of Health and Disease. Heat shock proteins (HSP) are essential molecules conserved through cellular evolution required for cells to survive the stresses encountered in the environment and in the tissues of the developing and aging organism. These proteins play the essential roles in stress of preventing the initiation of programmed cell death and repairing damage to the proteome permitting resumption of normal metabolism. Loss of the HSP is lethal either in the short-term in cases of acute stress or in the long-term when exposure to stress is chronic. Cells appear to walk a fi ne line in terms of HSP expression. If expression falls below a certain level, cells become sensitive to oxidative damage that infl uences aging and protein aggregation disease. If HSP levels rise above the normal range, infl ammatory and oncogenic changes occur. It is becoming clear that HSP are emerging as remarkably versatile mediators of health and disease. The aim of this series of volumes is to examine how HSP regulation and expression become altered in pathological states and how this may be remedied by pharmacological and other interventions.More information about this series at

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Importance of N- and C-terminal Regions of IbpA, Escherichia coli Small Heat Shock Protein, for Chaperone Function and Oligomerization

Cited by 47 publications

References 36 publications

The C‐terminal extension of Mycobacterium tuberculosis Hsp16.3 regulates its oligomerization, subunit exchange dynamics and chaperone function

The C‐terminal extension of Mycobacterium tuberculosis Hsp16.3 regulates its oligomerization, subunit exchange dynamics and chaperone function

Small Heat Shock Protein IbpB Acts as a Robust Chaperone in Living Cells by Hierarchically Activating Its Multi-type Substrate-binding Residues

The Big Book on Small Heat Shock Proteins

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