The expanding small heat-shock protein family, and structure predictions of the conserved “α-crystallin domain”

Abstract

The expanding small heat-shock protein family, and structure predictions of the conserved .. crystallin domain Caspers, G.J.M.; Leunissen, J.A.M.; de Jong, W.W. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract. The ever-increasing number of proteins identified as belonging to the family of small heat-shock proteins (shsps) and a-crystallins enables us to reassess the phylogeny of this ubiquitous protein family. While the prokaryotic and fungal representatives are not properly resolved, most of the plant and animal shsps and related proteins are clearly grouped in distinct clades, reflecting a history of repeated gene duplications. The members of the shsp family are characterized by the presence of a conserved homologous "cz-crystallin domain," which sometimes is present in duplicate. Predictions are made of secondary structure and solvent accessibility of this domain, which together with hydropathy profiles and intron positions support the presence of two similar hydrophobic a-sheet-rich motifs, connected by a hydrophilic co-helical region. Together with an overview of the newly characterized members of the shsp family, these data help to define this family as being involved as stable structural proteins and as molecular chaperones during normal development and induced under pathological and stressful conditions.

αA-Crystallin and αB-Crystallin Reside in Separate Subcellular Compartments in the Developing Ocular Lens

“…␣-Crystallin makes ϳ30% of the total protein in the vertebrate lens, but concentrations of each of its subunits, ␣A and ␣B, outside of the lens are comparatively much smaller and catalytic. These two polypeptides share 58% sequence identity and a common conserved ␣-crystallin domain, characteristic of the small heat shock family of proteins (30).…”

Chemical Signals of Vector Beetle Facilitate the Prevalence of a Native Fungus and the Invasive Pinewood Nematode

“…Among the molecular chaperone families, sHSP are the only known ATP-independent chaperones ( Jakob et al, 1993) and act as ''holdase'' for partially folded intermediates under stress conditions, which can be released and refolded at optimal conditions with the help of ATP-dependent chaperones (Wang and Spector, 2000;Cashikar et al, 2005). Small heat shock proteins are ubiquitously present in entire living organisms from bacteria to human cells (Caspers et al, 1995;Bult et al, 1996;Narberhaus, 2002;Laksanalamai and Robb, 2004).…”

Muscle Develops a Specific Form of Small Heat Shock Protein Complex Composed of MKBP/HSPB2 and HSPB3 during Myogenic Differentiation

“…HSPs with low molecular masses of 15-30 kDa are called small heat shock proteins (sHSPs); they commonly share a homologous sequence of about 80 amino acids called the "␣-crystallin domain" (5). Among mammalian sHSPs, HSP27 2 and ␣B-crystallin have been studied most intensely; they show chaperone-like activity in vitro (6 -8), and their expressions are induced in response to such diverse stimuli as heat shock, heavy metal exposure, and hypertonicity (9,10).…”