Mutation R120G in αB-crystallin, which is linked to a desmin-related myopathy, results in an irregular structure and defective chaperone-like function

Bova, Michael P.; Yaron, Orna; Huang, Qingling; Ding, Linlin; Haley, Dana A.; Stewart, Phoebe L.; Horwitz, Joseph

doi:10.1073/pnas.96.11.6137

Cited by 343 publications

(345 citation statements)

References 46 publications

Supporting

Mentioning

310

Contrasting

Unclassified

Order By: Relevance

“…It is worthwhile to mention that mutation of the neighboring residues often leads to significant changes in the structure and properties of sHsp. For instance, mutation R120G results in the change of oligomeric structure, chaperone-like activity, and intersubunit interaction of αB-crystallin (Kumar et al 1999;Perng et al 1999;Simon et al 2007;Michiel et al 2009;Bova et al 1999). Similar effects were observed in the case of HspB8 where mutations K137E and/or K141E were also accompanied by significant changes in the structure and properties (Kasakov et al 2007;Kim et al 2006).…”

Section: Discussionsupporting

confidence: 63%

The pivotal role of the β7 strand in the intersubunit contacts of different human small heat shock proteins

Mymrikov

Bukach

Seit-Nebi

et al. 2010

Cell Stress and Chaperones

View full text Add to dashboard Cite

Human αB-crystallin and small heat shock proteins HspB6 and HspB8 were mutated so that all endogenous Cys residues were replaced by Ser and the single Cys residue was inserted in a position homologous to that of Cys137 of human HspB1, i.e. in a position presumably located in the central part of β7 strand of the α-crystallin domain. The secondary, tertiary, and quaternary structures of thus obtained Cys-mutants as well as their chaperone-like activity were similar to those of their wildtype counterparts. Mild oxidation of Cys-mutants leads to formation of disulfide bond crosslinking neighboring monomers thus indicating participation of the β7 strand in intersubunit interaction. Oxidation weakly affects the secondary and tertiary structure, does not affect the quaternary structure of αB-crystallin and HspB6, and shifts equilibrium between monomer and dimer of HspB8 towards dimer formation. It is concluded that the β7 strand participates in the intersubunit interaction of four human small heat shock proteins (αB-crystallin, HspB1, HspB6, HspB8) having different structure of β2 strand of α-crystallin domain and different length and composition of variable N-and C-terminal tails.

show abstract

Section: Discussionsupporting

confidence: 63%

The pivotal role of the β7 strand in the intersubunit contacts of different human small heat shock proteins

Mymrikov

Bukach

Seit-Nebi

et al. 2010

Cell Stress and Chaperones

View full text Add to dashboard Cite

show abstract

“…77,78 Consistent with these observations, the chaperone-like ability of R116C and R120G was found substantially decreased. 79,80 The results reported here and also from earlier studies [73][74] reveal that the two mutants apparently display much weaker antiapoptotic ability. Our demonstration that the mutants have much less affinity to Bax and Bcl-X S provides an explanation.…”

Section: Antiapoptotic Mechanisms Of A-crystallinssupporting

confidence: 72%

Human αA- and αB-crystallins bind to Bax and Bcl-XS to sequester their translocation during staurosporine-induced apoptosis

et al. 2004

View full text Add to dashboard Cite

aA-and aB-crystallins are distinct antiapoptotic regulators. Regarding the antiapoptotic mechanisms, we have recently demonstrated that aB-crystallin interacts with the procaspase-3 and partially processed procaspase-3 to repress caspase-3 activation. Here, we demonstrate that human aA-and aBcrystallins prevent staurosporine-induced apoptosis through interactions with members of the Bcl-2 family. Using GST pulldown assays and coimmunoprecipitations, we demonstrated that a-crystallins bind to Bax and Bcl-X S both in vitro and in vivo. Human aA-and aB-crystallins display similar affinity to both proapoptotic regulators, and so are true with their antiapoptotic ability tested in human lens epithelial cells, human retina pigment epithelial cells (ARPE-19) and rat embryonic myocardium cells (H9c2) under treatment of staurosporine, etoposide or sorbitol. Two prominent mutants, R116C in aA-crystallin and R120G, in aB-crystallin display much weaker affinity to Bax and Bcl-X S . Through the interaction, a-crystallins prevent the translocation of Bax and Bcl-X S from cytosol into mitochondria during staurosporine-induced apoptosis. As a result, a-crystallins preserve the integrity of mitochondria, restrict release of cytochrome c, repress activation of caspase-3 and block degradation of PARP. Thus, our results demonstrate a novel antiapoptotic mechanism for a-crystallins. Keywords: aA-crystallin; R116C; aB-crystallin; R120G; Bax; Bcl-X S Abbreviations: a-crystallin, alpha-crystallin; GFP, green fluorescence protein; HaA, human aA-crystallin; HaB, human aB-crystallin; GFP-HaA, green fluorescence and human aAcrystallin fusion protein; GFP-HaB, green fluorescence and human aB-crystallin fusion protein; MEM, Eagle's minimal essential medium; PAGE, polyacrylamide gel electrophoresis; PBS, phosphate-buffered saline; PMSF, phenylmethylsufonyl fluoride; HLE, human lens epithelial cells; SDS, sodium dodecylsulfate; TBS, tris-buffered saline; TBS-T, tris-buffered saline with tween-20.

show abstract

“…Structural and functional studies indicate that the mutant alphaBcrystallin had reduced or completely lost chaperone function. 72,73 AlphaB-crystallin lost the ability to interact with alphaA-crystallin, but strongly interacted with wild type alphaBcrystallin, 74 suggesting a mechanism for dominant negative effect. In transiently transfected cells, mutant alphaB-crystallin accumulated in inclusion bodies (aggresomes) that may be due to misfolding of the mutant protein.…”

Section: Cryab Mutationsmentioning

confidence: 98%

“…They help to restore proteins to their native conformation after these proteins have been misfolded by heat, ischemia, chemotoxicity, or other cellular stresses. 72 An in vitro chaperone assay demonstrated that the mutant p.Arg120Gly alphaB-crystallin becomes functionally deficient. 89 Expression of the mutant alphaB-crystallin in SW13 and BHK21 cells leads to formation of abnormal aggregates that contain both desmin and alphaB-crystallin.…”

Section: Role Of Alphab-crystallinmentioning

confidence: 99%

Intermediate Filament Diseases: Desminopathy

Goldfarb

Olivé

Vicart³

et al. 2008

Advances in Experimental Medicine and Biology

104

View full text Add to dashboard Cite

Desminopathy is one of the most common intermediate filament human disorders associated with mutations in closely interacting proteins, desmin and alphaB-crystallin. The inheritance pattern in familial desminopathy is characterized as autosomal dominant or autosomal recessive, but many cases have no family history. At least some and likely most sporadic desminopathy cases are associated with de novo DES mutations. The age of disease onset and rate of progression may vary depending on the type of inheritance and location of the causative mutation. Typically, the illness presents with lower and later upper limb muscle weakness slowly spreading to involve truncal, neckflexor, facial and bulbar muscles. Skeletal myopathy is often combined with cardiomyopathy manifested by conduction blocks, arrhythmias and chronic heart failure resulting in premature sudden death. Respiratory muscle weakness is a major complication in some patients. Sections of the affected skeletal and cardiac muscles show abnormal fibre areas containing chimeric aggregates consisting of desmin and other cytoskeletal proteins. Various DES gene mutations: point mutations, an insertion, small in-frame deletions and a larger exon-skipping deletion, have been identified in desminopathy patients. The majority of these mutations are located in conserved alpha-helical segments, but additional mutations have recently been identified in the tail domain. Filament and network assembly studies indicate that most but not all disease-causing mutations make desmin assembly-incompetent and able to disrupt a pre-existing filamentous network in dominant-negative fashion. AlphaBcrystallin serves as a chaperone for desmin preventing its aggregation under various forms of stress; mutant CRYAB causes cardiac and skeletal myopathies identical to those resulting from DES mutations.

show abstract

Mutation R120G in αB-crystallin, which is linked to a desmin-related myopathy, results in an irregular structure and defective chaperone-like function

Cited by 343 publications

References 46 publications

The pivotal role of the β7 strand in the intersubunit contacts of different human small heat shock proteins

The pivotal role of the β7 strand in the intersubunit contacts of different human small heat shock proteins

Human αA- and αB-crystallins bind to Bax and Bcl-XS to sequester their translocation during staurosporine-induced apoptosis

Intermediate Filament Diseases: Desminopathy

Contact Info

Product

Resources

About