Monitoring the Interaction between β2-Microglobulin and the Molecular Chaperone αB-crystallin by NMR and Mass Spectrometry

Esposito, Gennaro; Garvey, Megan; Alverdi, Vera; Pettirossi, Fabio; Corazza, Alessandra; Fogolari, Federico; Polano, Maurizio; Mangione, Palma; Giorgetti, Sofia; Stoppini, Monica; Rekas, Agata; Bellotti, Vittorio; Heck, Albert J. R.; Carver, John A.

doi:10.1074/jbc.m112.448639

Cited by 36 publications

(44 citation statements)

References 70 publications

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“…The interaction of αBc with amyloid fibril-forming proteins, e.g. α-synuclein, ataxin-3, apolipoprotein C-II, kappa-casein and β2-microgobulin, is such a situation (Cox et al 2016;Esposito et al 2013;Hatters et al 2001;Rekas et al 2004;Rekas et al 2007;Robertson et al 2010). The variation in sHsp chaperone mechanism depending on conditions and the degree of unfolding of the target protein is consistent with various studies.…”

Section: The N-and C-terminal Flanking Regions In Shspssupporting

confidence: 72%

The functional roles of the unstructured N- and C-terminal regions in αB-crystallin and other mammalian small heat-shock proteins

Carver

Grosas

Ecroyd

et al. 2017

Cell Stress and Chaperones

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Small heat-shock proteins (sHsps), such as αB-crystallin, are one of the major classes of molecular chaperone proteins. In vivo, under conditions of cellular stress, sHsps are the principal defence proteins that prevent large-scale protein aggregation. Progress in determining the structure of sHsps has been significant recently, particularly in relation to the conserved, central and β-sheet structured α-crystallin domain (ACD). However, an understanding of the structure and functional roles of the N-and C-terminal flanking regions has proved elusive mainly because of their unstructured and dynamic nature. In this paper, we propose functional roles for both flanking regions, based around three properties: (i) they act in a localised crowding manner to regulate interactions with target proteins during chaperone action, (ii) they protect the ACD from deleterious amyloid fibril formation and (iii) the flexibility of these regions, particularly at the extreme C-terminus in mammalian sHsps, provides solubility for sHsps under chaperone and nonchaperone conditions. In the eye lens, these properties are highly relevant as the crystallin proteins, in particular the two sHsps αA-and αB-crystallin, are present at very high concentrations.

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Section: The N-and C-terminal Flanking Regions In Shspssupporting

confidence: 72%

The functional roles of the unstructured N- and C-terminal regions in αB-crystallin and other mammalian small heat-shock proteins

Carver

Grosas

Ecroyd

et al. 2017

Cell Stress and Chaperones

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“…Furthermore, besides the heavy α-crystallin oligomers, the lower molecular mass β/γ-crystallins were found in these fractions too, confirming the size exclusion conclusions regarding protein composition of the first peak. This finding demonstrates that α-crystallins form stable complexes with β/γ-crystallins and lends support to reports detailing the chaperone-like function of α-crystallins2930.…”

Section: Resultssupporting

confidence: 88%

Tryptophan and Non-Tryptophan Fluorescence of the Eye Lens Proteins Provides Diagnostics of Cataract at the Molecular Level

Gakamsky

Duncan

Howarth

et al. 2017

Sci Rep

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The chemical nature of the non-tryptophan (non-Trp) fluorescence of porcine and human eye lens proteins was identified by Mass Spectrometry (MS) and Fluorescence Steady-State and Lifetime spectroscopy as post-translational modifications (PTM) of Trp and Arg amino acid residues. Fluorescence intensity profiles measured along the optical axis of human eye lenses with age-related nuclear cataract showed increasing concentration of fluorescent PTM towards the lens centre in accord with the increased optical density in the lens nucleolus. Significant differences between fluorescence lifetimes of “free” Trp derivatives hydroxytryptophan (OH-Trp), N-formylkynurenine (NFK), kynurenine (Kyn), hydroxykynurenine (OH-Kyn) and their residues were observed. Notably, the lifetime constants of these residues in a model peptide were considerably greater than those of their “free” counterparts. Fluorescence of Trp, its derivatives and argpyrimidine (ArgP) can be excited at the red edge of the Trp absorption band which allows normalisation of the emission spectra of these PTMs to the fluorescence intensity of Trp, to determine semi-quantitatively their concentration. We show that the cumulative fraction of OH-Trp, NFK and ArgP emission dominates the total fluorescence spectrum in both emulsified post-surgical human cataract protein samples, as well as in whole lenses and that this correlates strongly with cataract grade and age.

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“…by binding to fibrils they facilitate their packing into inclusions, thereby limiting fibril fragmentation and secondary nucleation and providing an alternative protective mechanism to the cell. Recently αBc has also been shown to promote the dissociation of potentially toxic β 2 -microglobulin oligomers into monomers, highlighting another role these chaperones may have in cells to protect them from the adverse effects of protein aggregation [111].…”

Section: The Chaperone Mechanism Of Shspsmentioning

confidence: 99%

Small heat-shock proteins: important players in regulating cellular proteostasis

Treweek

Meehan

Ecroyd

et al. 2014

Cell. Mol. Life Sci.

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Small heat-shock proteins (sHsps) are a diverse family of intra-cellular molecular chaperone proteins that play a critical role in mitigating and preventing protein aggregation under stress conditions such as elevated temperature, oxidation and infection. In doing so, they assist in the maintenance of protein homeostasis (proteostasis) thereby avoiding the deleterious effects that result from loss of protein function and/or protein aggregation. The chaperone properties of sHsps are therefore employed extensively in many tissues to prevent the development of diseases associated with protein aggregation. Significant progress has been made of late in understanding the structure and chaperone mechanism of sHsps. In this review, we discuss some of these advances, with a focus on mammalian sHsp hetero-oligomerisation, the mechanism by which sHsps act as molecular chaperones to prevent both amorphous and fibrillar protein aggregation, and the role of posttranslational modifications in sHsp chaperone function, particularly in the context of disease. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 Abstract (word count = 159)Small heat-shock proteins (sHsps) are a diverse family of intracellular molecular chaperone proteins that play a critical role in preventing protein unfolding, misfolding and aggregation, particularly under stress conditions such as elevated temperature, oxidation and infection. In doing so, they assist in the maintenance of protein homeostasis (proteostasis) and thereby avoid the deleterious effects that result from loss of protein function and/or protein aggregation. The chaperone properties of sHsps are therefore employed extensively in many tissues to prevent the development of diseases associated with protein aggregation. There has been much research into the structure and mechanism of chaperone action of sHsps over approximately the past 30 years, and significant progress has been made of late, however, there are still many unanswered questions relating to these aspects of sHsps. In this review, we outline some of the recent advances in understanding the structure and function of mammalian sHsps, particularly in the context of their many and varied roles in disease.

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Monitoring the Interaction between β2-Microglobulin and the Molecular Chaperone αB-crystallin by NMR and Mass Spectrometry

Cited by 36 publications

References 70 publications

The functional roles of the unstructured N- and C-terminal regions in αB-crystallin and other mammalian small heat-shock proteins

The functional roles of the unstructured N- and C-terminal regions in αB-crystallin and other mammalian small heat-shock proteins

Tryptophan and Non-Tryptophan Fluorescence of the Eye Lens Proteins Provides Diagnostics of Cataract at the Molecular Level

Small heat-shock proteins: important players in regulating cellular proteostasis

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