Heat shock protein gene expression during Xenopus development

Heikkila, John J.; Ohan, Nicholas; Tam, Ying K.; Ali, Adnan Hussein

doi:10.1007/pl00000573

Cited by 65 publications

(29 citation statements)

References 73 publications

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“…The by no means complete list includes eye lens transparency (33); thermotolerance (169,171,177,198,248,261,270,332,362); resistance to apoptosis (10,35,45,(199)(200)(201); cytoskeleton modulation (20,104,172,184,207,232); prevention of amyloid formation (165,307); human diseases (48); various developmental processes in animals (11,118,181,185,203), plants (349), and bacteria (115); protection against oxidative stress (109,259); desiccation tolerance (354); protection of the photosynthetic apparatus (113,221) or of mitochondrial NADH:ubiquinone oxidoreductase (complex I) (68,69); microbial pathogenicity (2,54,228,283,342,363,365); symbiotic and pathogenic plantmicrobe interactions (16,…”

Section: Other Functions Of ␣-Heat Shock Proteinsmentioning

confidence: 99%

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

Narberhaus

2002

Microbiol Mol Biol Rev

503

415

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SUMMARY α-Crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. Subsequently, they have been found in many, but not all, members of the Archaea, Bacteria, and Eucarya. Most members of the diverse α-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kDa; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the so-called α-crystallin domain; and (iv) molecular chaperone activity. Since α-crystallins are induced by a temperature upshift in many organisms, they are often referred to as small heat shock proteins (sHsps) or, more accurately, α-Hsps. α-Crystallins are integrated into a highly flexible and synergistic multichaperone network evolved to secure protein quality control in the cell. Their chaperone activity is limited to the binding of unfolding intermediates in order to protect them from irreversible aggregation. Productive release and refolding of captured proteins into the native state requires close cooperation with other cellular chaperones. In addition, α-Hsps seem to play an important role in membrane stabilization. The review compiles information on the abundance, sequence conservation, regulation, structure, and function of α-Hsps with an emphasis on the microbial members of this chaperone family.

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Section: Other Functions Of ␣-Heat Shock Proteinsmentioning

confidence: 99%

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

Narberhaus

2002

Microbiol Mol Biol Rev

503

415

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“…The number of genes encoding small heat shock/h-crystallin proteins differs from species to species [10]. Plants have five families of genes for these proteins [15,16,26] and there are multiple genes for the small heat shock/h-crystallin proteins in Escherichia coli [66], Saccharomyces cere6isiae [10,17], Drosophila [57], Caenorhabditis elegans [60,61,67], Xenopus [14,63,68], Artemia [69], and mammals [10,18,70]. The genes have evolved through duplication and subsequent modification [10,24].…”

Section: Introductionmentioning

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

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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.

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“…Our laboratory has characterized hsp gene expression in embryos and cultured cells of the aquatic frog, Xenopus laevis (Heikkila et al 1997;Lang et al 1999;2000;Ovakim and Heikkila 2003;Heikkila 2003;Gellalchew and Heikkila 2005;Manwell and Heikkila 2007;Young et al 2009). These studies examined a number of different aspects of heat shock and chemical stress-induced expression of hsp30 and hsp70 genes during early frog development as well as in an A6 kidney epithelial cell line.…”

Section: Introductionmentioning

confidence: 99%

Proteasome inhibition induces hsp30 and hsp70 gene expression as well as the acquisition of thermotolerance in Xenopus laevis A6 cells

Young

Heikkila

2010

Cell Stress and Chaperones

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Previous studies have shown that inhibiting the activity of the proteasome leads to the accumulation of damaged or unfolded proteins within the cell. In this study, we report that proteasome inhibitors, lactacystin and carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG132), induced the accumulation of ubiquitinated proteins as well as a dose-and time-dependent increase in the relative levels of heat shock protein (HSP)30 and HSP70 and their respective mRNAs in Xenopus laevis A6 kidney epithelial cells. In A6 cells recovering from MG132 exposure, HSP30 and HSP70 levels were still elevated after 24 h but decreased substantially after 48 h. The activation of heat shock factor 1 (HSF1) may be involved in MG132-induced hsp gene expression in A6 cells since KNK437, a HSF1 inhibitor, repressed the accumulation of HSP30 and HSP70. Exposing A6 cells to simultaneous MG132 and mild heat shock enhanced the accumulation of HSP30 and HSP70 to a much greater extent than with each stressor alone. Immunocytochemical studies determined that HSP30 was localized primarily in the cytoplasm of lactacystin-or MG132-treated cells. In some cells treated with higher concentrations of MG132 or lactacystin, we observed in the cortical cytoplasm (1) relatively large HSP30 staining structures, (2) colocalization of actin and HSP30, and (3) cytoplasmic areas that were devoid of HSP30. Lastly, MG132 treatment of A6 cells conferred a state of thermotolerance such that they were able to survive a subsequent thermal challenge.

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Heat shock protein gene expression during Xenopus development

Cited by 65 publications

References 73 publications

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

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

Proteasome inhibition induces hsp30 and hsp70 gene expression as well as the acquisition of thermotolerance in Xenopus laevis A6 cells

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