A comparison of structural relationships among α-crystallin, human Hsp27, γ-crystallins and βB2-crystallin

Singh, Kamalendra; Zewge, Daniel; Groth-Vasselli, Barbara; Farnsworth, Patricia N.

doi:10.1016/s0141-8130(96)01131-2

Cited by 19 publications

(10 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Secondary structure within the amino terminus of h-crystallin and Hsp27 is less similar than in the h-crystallin domain; correspondingly, the primary structure of the amino domain is not as well conserved [127]. Moreover, the conformation of the Hsp27 h-crystallin domain is more stable than its carboxy-terminal extension [127].…”

Section: Secondary-structure Properties Of Small Heat Shock/-crystallmentioning

confidence: 99%

“…Far-UV circular dichroism (CD)-spectra [3, 96,105,120,127,128] and flexibility plots [127] show that the secondary structure of h-crystallins, Hsp27, and other small heat shock/h-crystallin proteins is enriched in i-pleated sheets, a finding reached independently by modelling of sequence data [10,18,69]. Secondary structure within the amino terminus of h-crystallin and Hsp27 is less similar than in the h-crystallin domain; correspondingly, the primary structure of the amino domain is not as well conserved [127].…”

Section: Secondary-structure Properties Of Small Heat Shock/-crystallmentioning

confidence: 99%

See 1 more Smart Citation

Structure and function of small heat shock/α-crystallin proteins: established concepts and emerging ideas

MacRae¹

2000

CMLS, Cell. Mol. Life Sci.

235

185

View full text Add to dashboard Cite

Small heat shock/alpha-crystallin proteins are defined by conserved sequence of approximately 90 amino acid residues, termed the alpha-crystallin domain, which is bounded by variable amino- and carboxy-terminal extensions. These proteins form oligomers, most of uncertain quaternary structure, and oligomerization is prerequisite to their function as molecular chaperones. Sequence modelling and physical analyses show that the secondary structure of small heat shock/alpha-crystallin proteins is predominately beta-pleated sheet. Crystallography, site-directed spin-labelling and yeast two-hybrid selection demonstrate regions of secondary structure within the alpha-crystallin domain that interact during oligomer assembly, a process also dependent on the amino terminus. Oligomers are dynamic, exhibiting subunit exchange and organizational plasticity, perhaps leading to functional diversity. Exposure of hydrophobic residues by structural modification facilitates chaperoning where denaturing proteins in the molten globule state associate with oligomers. The flexible carboxy-terminal extension contributes to chaperone activity by enhancing the solubility of small heat shock/alpha-crystallin proteins. Site-directed mutagenesis has yielded proteins where the effect of the change on structure and function depends upon the residue modified, the organism under study and the analytical techniques used. Most revealing, substitution of a conserved arginine residue within the alpha-crystallin domain has a major impact on quaternary structure and chaperone action probably through realignment of beta-sheets. These mutations are linked to inherited diseases. Oligomer size is regulated by a stress-responsive cascade including MAPKAP kinase 2/3 and p38. Phosphorylation of small heat shock/alpha-crystallin proteins has important consequences within stressed cells, especially for microfilaments.

show abstract

Section: Secondary-structure Properties Of Small Heat Shock/-crystallmentioning

confidence: 99%

Section: Secondary-structure Properties Of Small Heat Shock/-crystallmentioning

confidence: 99%

Structure and function of small heat shock/α-crystallin proteins: established concepts and emerging ideas

MacRae¹

2000

CMLS, Cell. Mol. Life Sci.

235

185

View full text Add to dashboard Cite

show abstract

“…As such, it is the first report of a small heat shock/α-crystallin protein in scleractinian corals. These proteins are defined by an α-crystallin domain, a conserved sequence of 80-100 amino acid residues enriched in β-pleated sheet secondary structure (de Jong et al 1993;Jakob and Buchner 1994;Caspers et al 1995;Singh et al 1996;Liang et al 1997aLiang et al , 1997b. The small heat shock/ α-crystallin proteins function as molecular chaperones, wherein they bind denaturing proteins and prevent their aggregation within cells under stress (Lee et al 1997;Muchowski et al 1997;Plater et al 1996;Rajaraman et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Identification of a small heat shock/α-crystallin protein in the scleractinian coralMadracis mirabilis(Duch. and Mitch.)

Branton¹,

MacRae²,

Lipschultz³

et al. 1999

Can. J. Zool.

View full text Add to dashboard Cite

Immunological evidence is provided for the first time of a small heat shock/α-crystallin protein in the scleractinian coral Madracis mirabilis. The protein, termed cp26, had a molecular weight of 26 000; it reacted with an antibody raised to a small heat shock/α-crystallin protein from Artemia franciscana and its production in corals was temperature sensitive. Corals collected from seawater at 25.5 o C or lower lacked cp26, but the protein was produced in some of these animals when they were heat shocked experimentally. When exposed naturally to high environmental temperatures for relatively short times, corals contained cp26 and responded to heat shock in the laboratory. Corals growing at elevated temperatures tended to die when subjected to additional heat stress. Specifically, M. mirabilis died at about 31-33 o C, as indicated by visual inspection of the animals, low recovery of protein in cell-free extracts, and loss of protein bands in SDS-polyacrylamide gels. Death was accompanied by the appearance of a diffuse, unidentified protein band on western blots that reacted with an antibody to cp26. Madracis mirabilis clearly reacts to heat shock by production of cp26; further study is required to determine if this small heat shock/α-crystallin protein will be a useful biomarker of stress in corals.Résumé : Nous avons maintenant une preuve immunologique de l'existence d'une petite protéine α-cristalline de choc thermique chez le corail scléractinien Madracis mirabilis. La protéine, appelée cp26, a une masse moléculaire de 26 000; elle réagit à l'anticorps d'une petite protéine α-cristalline de choc thermique d'Artemia franciscana et sa production chez les coraux est sensible à la température. Les coraux récoltés dans l'eau de mer à 25,5 o C ou moins ne possèdent pas la protéine cp26, mais celle-ci est synthétisée lors que les coraux sont soumis à un choc thermique expérimental. Lorsqu'ils sont exposés naturellement à des températures ambiantes élevées pour des périodes relativement courtes, les coraux contiennent la protéine et réagissent lorsqu'ils sont soumis à un choc thermique en laboratoire. Les coraux en développement à des températures élevées ont tendance à mourir s'ils sont soumis à des stress thermiques additionnels. Spécifiquement, M. mirabilis meurt à environ 31-33 o C si l'on se fie à l'examen visuel des animaux, à la faible concentration des protéines dans les extraits sans cellules et à la perte des bandes protéiniques dans les gels de SDS-polyacrylamide. À la mort, il se forme aussi sur les transferts western une bande indéterminée diffuse de protéine réagissant à l'anticorps de cp26. Madracis mirabilis réagit donc aux chocs thermiques en produisant la protéine cp26; des études subséquentes pourront démontrer si cette petite protéine α-cristalline de choc thermique peut servir de marqueur biologique du stress chez les coraux.[Traduit par la Rédaction] Branton et al. 682

show abstract

“…2) [1,15]. This region is a highly structured β-pleated sheet with several contact points allowing oligomer formation and stabilization [16].…”

Section: Hsp27: Molecular Characteristics and Functional Regulationmentioning

confidence: 99%

HSP27: Mechanisms of Cellular Protection Against Neuronal Injury

Stetler¹,

Gao²,

Signore³

et al. 2009

CMM

117

105

View full text Add to dashboard Cite

The heat shock protein (HSP) family has long been associated with a generalized cellular stress response, particularly in terms of recognizing and chaperoning misfolded proteins. While HSPs in general appear to be protective, HSP27 has recently emerged as a particularly potent neuroprotectant in a number of diverse neurological disorders, ranging from ALS to stroke. Although its robust protective effect on a number of insults has been recognized, the mechanisms and regulation of HSP27's protective actions are still undergoing intense investigation. On the basis of recent studies, HSP27 appears to have a dynamic and diverse range of function in cellular survival. This review provides a forum to compare and contrast recent literature exploring the protective mechanism and regulation of HSP27, focusing on neurological disorders in particular, as they represent a range from protein aggregate-associated diseases to acute stress.

show abstract

A comparison of structural relationships among α-crystallin, human Hsp27, γ-crystallins and βB2-crystallin

Cited by 19 publications

References 39 publications

Structure and function of small heat shock/α-crystallin proteins: established concepts and emerging ideas

Structure and function of small heat shock/α-crystallin proteins: established concepts and emerging ideas

Identification of a small heat shock/α-crystallin protein in the scleractinian coralMadracis mirabilis(Duch. and Mitch.)

HSP27: Mechanisms of Cellular Protection Against Neuronal Injury

Contact Info

Product

Resources

About