Hsp27 and Talk:Krystal Meyers: Difference between pages
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{{Christianmusic|Contemporary Christian-work-group=yes|class=start|importance=}} |
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'''Hsp27''' is a [[chaperone (protein)|chaperone]] of the [[sHsp]] (small [[heat shock protein]]) group among [[ubiquitin]], α-[[crystallin]], [[Hsp20]] and others. The common functions of sHsps are chaperone activity, thermotolerance, inhibition of [[apoptosis]], regulation of cell development, and [[Cellular differentiation|cell differentiation]]. They also take part in [[signal transduction]]. |
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==Jeremy Shum sex scandal coverup== |
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==Structure of sHsps== |
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I was wondering whether there were any reputable sources that could be quoted in regard to the sex scandal cover-up (http://groups.google.com/group/uk.music.christian/msg/031b64cadce498fd). Apparently, Sony BMG has, like the Brooke Fraser sex scandal, tried to cover everything up again. It seems like the sex video has been entirely removed off the internet.[[User:Wrickwareen|Wrickwareen]] ([[User talk:Wrickwareen|talk]]) 05:02, 10 October 2008 (UTC) |
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sHsps have some structural features in common: Very characteristic is a homologous and highly conserved amino acid sequence, the so-called α-crystallin-domain at the [[C-terminus]]. These sequences consist of 80 to 100 residues with a homology between 20% and 60% and form [[beta sheet|β-sheets]], which are important for the formation of stable dimers.<ref name=kim>Kim KK, Kim R, Kim S. Crystal structure of a small heat shock protein. ''Nature''. '''394'''(6693):595-9. 1998.</ref><ref name=vanmonfort>Van Montfort R, Slingsby C, Vierling E. Structure and function of the small heat shock protein/alpha-crystallin family of molecular chaperones. ''Adv Protein Chem''. '''59''':105-56. 2001.</ref> |
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== Source of article content == |
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The [[N-terminus]] consists of a less conserved region, the so-called WD/EPF domain, followed by a short variable sequence with a rather conservative site near the C-terminus of this domain. The C-terminal part of the sHsps consists of the above mentioned α-crystallin domain, followed by a variable sequence with high motility and flexibility.<ref name=gusev>Gusev NB, Bogatcheva NV, Marston SB. Structure and properties of small heat shock proteins (sHsp) and their interaction with cytoskeleton proteins. ''Biochemistry (Mosc)''. '''67(5)''':511-9. 2002.</ref> |
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I have checked the article and all the text beyond the introductory paragraph is a cut a paste job from official site's biography. If no one does anything about it in next week, I will remove the text and add a music artist template reducing this article to stub.--[[User:Kevin586|Kevin586]] 15:09, 21 June 2007 (UTC) |
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This C-terminal tail appears in many mammalian sHsps (e.g. mouse Hsp25, αA-crystallin) and has no homology. It is highly flexible and polar because of its negative charges.<ref name=liao>Liao JH, Lee JS, Chiou SH. C-terminal lysine truncation increases thermostability and enhances chaperone-like function of porcine αB-crystallin. ''Biochem Biophys Res Commun''. '''297(2)''':309-16. 2002.</ref> Probably it functions as a mediator of solubility for hydrophobic sHsps and it stabilizes the protein and protein/substrate complexes. This was shown by elimination of the C-terminal tail in Hsp27Δ182-205 <ref name=lelj>Lelj-Garolla B, Mauk AG. Self-association of a small heat shock protein. ''J Mol Biol''. '''345(3)''':631-42. 2005.</ref> and in Hsp25Δ18.<ref name=lindner>Lindner RA, Carver JA, Ehrnsperger M, Buchner J, Esposito G, Behlke J, Lutsch G, Kotlyarov A, Gaestel M. Mouse Hsp25, a small shock protein. The role of its C-terminal extension in oligomerization and chaperone action. ''Eur J Biochem''. '''267(7)''':1923-32. 2000.</ref> |
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== Lack of sources in general == |
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==Oligomerization== |
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I cannot find anywhere on the Internet that Krystal Meyers considers herself "the real rock chick". |
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The N-terminus with its WD/EPF-region is essential for the development of high molecular [[oligomers]],<ref name=haslbeck>Haslbeck M. sHsps and their role in the chaperone network. ''Cell Mol Life Sci''. '''59(10)''':1649-57. 2002.</ref><ref name=theriault>Theriault JR, Lambert H, Chavez-Zobel AT, Charest G, Lavigne P, Landry J. Essential role of the NH2-terminal WD/EPF motif in the phosphorylation-activated protective function of mammalian Hsp27. ''J Biol Chem''. '''279(22)''':23463-71. 2004.</ref> which exclusively have chaperone activity ''in vitro''. Hsp27-oligomers probably consist of stable [[dimers]], which are formed by two α-crystallin-domains of neighbouring [[monomers]],<ref name=gusev/> which was shown with the proteins MjHSP16.5 from [http://microbewiki.kenyon.edu/mediawiki-1.6.6/index.php/Methanococcus Methanocaldococcus jannaschii]<ref name=kim/> and wheat Hsp16.9.<ref name=vanmonfort/> The stable dimers aggregate to [[tetramer]]s and finally form unstable oligomers. |
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A citation is needed for Anticonformity and the Christian camp. |
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I also suggest a "Comparison with Avril Lavigne" or "Comparison with other rock chicks" section. |
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--[[User:Superkirbyartist|Superkirbyartist]] ([[User talk:Superkirbyartist|talk]]) 23:27, 20 November 2007 (UTC)Krystal Roxxxxxxxxxx!!!!!!! |
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== YOU ROX!!!!!!! == |
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The oligomerization of Hsp27 is a dynamic process: There is a balance between stable dimers respectively tetramers and instable oligomers (up to 800 [[kilodalton|kDa]]) consisting of 16 to 32 subunits and a high exchange rate of subunits.<ref name=theriault/><ref name=ehrnsperger>Ehrnsperger M, Lilie H, Gaestel M, Buchner J. The dynamics of Hsp25 quaternary structure. Structure and function of different oligomeric species. ''J Biol Chem''. '''274(21)''':14867-74. 1999.</ref><ref name=rogalla>Rogalla T, Ehrnsperger M, Preville X, Kotlyarov A, Lutsch G, Ducasse C, Paul C, Wieske M, Arrigo AP, Buchner J, Gaestel M. Regulation of Hsp27 oligomerization, chaperone function, and protective activity against oxidative stress/tumor necrosis factor alpha by phosphorylation. ''J Biol Chem''. '''274(27)''':18947-56. 1999.</ref> The oligomerization depends on the physiology of the cells, the [[phosphorylation]] status of Hsp27 and the exposure to stress. Stress induces an increase of [[gene expression|expression]] (after hours) and phosphorylation (after several minutes) of Hsp27. Stimulation of the p38 [[MAP kinase]] cascade by differentiating agents, [[mitogens]], [[inflammatory]] [[cytokines]] such as [[TNF]]α and [[Interleukin 1|IL-1β]], [[hydrogen peroxide]] and other [[oxidants]],<ref name=garrido>Garrido C. Size matters: of the small HSP27 and its large oligomers. ''Cell Death Differ''. '''9(5)''':483-5. 2002.</ref> leads to the activation of MAPKAP kinases 2 and 3 which directly phosphorylate mammalian sHsps.<ref name=rogalla/> The phosphorylation plays an important role for the formation of oligomers in exponentially growing cells ''in vitro'', but the oligomerization in [[tumor]] cells growing ''in vivo'' or growing at confluence ''in vitro'' is dependent on cell-cell contact, but not on the phosphorylation status.<ref name=bruey>Bruey JM, Paul C, Fromentin A, Hilpert S, Arrigo AP, Solary E, Garrido C. Differential regulation of HSP27 oligomerization in tumor cells grown in vitro and in vivo. ''Oncogene''. '''19(42)''':4855-63. 2000.</ref> |
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your music iz off the chain .!!!! <span class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/67.163.13.2|67.163.13.2]] ([[User talk:67.163.13.2|talk]]) 20:20, 14 September 2008 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot--> |
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In all probability, the oligomerization status is connected with the chaperone activity: aggregates of large oligomers have high chaperone activity, whereas dimers have no chaperone activity.<ref name=gusev/> Therefore it is clear, that a formation of large aggregates takes place under heat shock.<ref name=ehrnsperger/> |
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==Cellular Localization== |
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Hsp27 appears in many [[cell type]]s, especially all types of [[muscle]] cells. It is located mainly in the [[cytosol]], but also in the perinuclear region, [[endoplasmatic reticulum]], and [[cell nucleus|nucleus]]. It is overexpressed during different stages of cell differentiation and development. This suggests an essential role for Hsp27 in the differentiation of tissues. |
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An affinity of high expression levels of different phosphorylated Hsp27 species and [[Muscle diseases|muscle]]/[[neurodegenerative diseases]] and various [[cancers]] was observed.<ref name=sarto>Sarto C, Binz PA, Mocarelli P. Heat shock proteins in human cancer. ''Electrophoresis''. '''21(6)''':1218-26. 2000.</ref> High expression levels possibly are in inverse relation with [[cell proliferation]], [[metastasis]], and resistance to [[chemotherapy]].<ref name=vargas>Vargas-Roig LM, Fanelli MA, Lopez LA, Gago FE, Tello O, Aznar JC, Ciocca DR. Heat shock proteins and cell proliferation in human breast cancer biopsy samples. ''Cancer Detect Prev''. '''21(5)''':441-51. 1997.</ref> High levels of Hsp27 were also found in sera of [[breast cancer]] patients <ref name=rui>Rui Z, Jian-Guo J, Yuan-Peng T, Hai P, Bing-Gen R. Use of serological proteomic methods to find biomarkers associated with breast cancer. ''Proteomics''. '''3(4)''':433-9. 2003.</ref>; therefore Hsp27 could be a potential diagnostical marker. |
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==Functions== |
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General functions are the thermotolerance ''in vivo'', the cytoprotection, and the support of cell survival under stress conditions. Special functions are manifold and complex. ''In vitro'' it acts as an [[Adenosine triphosphate|ATP]]-independent chaperone by inhibiting protein aggregation and by stabilizing partially denatured proteins, which ensures refolding by the [[Hsp70]]-complex. |
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Hsp27 is also involved in the [[apoptosis|apoptotic]] signalling pathway. Hsp27 interacts with the outer [[mitochondrion|mitochondrial]] membranes and interferes with the activation of [[cytochrome c]]/[[Apaf-1]]/dATP complex and therefore inhibits the activation of [[caspase|procaspase-9]].<ref name=sarto/> The phosphorylated form of Hsp27 inhibits [[Daxx]] apoptotic protein and prevents the association of Daxx with Fas and Ask1.<ref name=charette>Charette SJ, Lavoie JN, Lambert H, Landry J. Inhibition of Daxx-mediated apoptosis by heat shock protein 27. ''Mol Cell Biol''. '''20(20)''':7602-12. 2000.</ref> |
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A well documented function of Hsp27 is the interaction with [[actin]] and intermediate filaments. It prevents the formation of non-covalent filament/filament interactions of the intermediate filaments and protects actin filaments from fragmentation. It also preserves the focal contacts fixed at the [[cell membrane]].<ref name=sarto/> |
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Another function of Hsp27 is the activation of the [[proteasome]]. It speeds up the degradation of irreversibly denatured proteins and junkproteins by binding to [[ubiquitin|ubiquitinated]] proteins and to the 26S proteasome. Hsp27 enhances the activation of the [[NF-κB]] pathway, that controls a lot of processes, such as cell growth and inflammatory and stress responses.<ref name=parcellier>Parcellier A, Schmitt E, Gurbuxani S, Seigneurin-Berny D, Pance A, Chantome A, Plenchette S, Khochbin S, Solary E, Garrido C. HSP27 is a ubiquitin-binding protein involved in I-kappaBalpha proteasomal degradation. ''Mol Cell Biol''. '''23(16)''':5790-802. 2003.</ref> |
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The cytoprotective properties of Hsp27 result from its ability to modulate [[reactive oxygen species]] and to raise [[glutathione]] levels. |
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Probably Hsp27 – among other chaperones – is involved in the process of cell differentiation.<ref name=arrigo>Arrigo AP. In search of the molecular mechanism by which small stress proteins counteract apoptosis during cellular differentiation. ''J Cell Biochem''. '''94(2)''':241-6. 2005.</ref> Changes of Hsp27 levels were observed in [[Ehrlich ascite]] cells, [[embryonic stem cells]], normal [[B-cells]], B-[[lymphoma]] cells, [[osteoblasts]], [[keratinocytes]] etc. The upregulation of Hsp27 correlates with the rate of phosphorylation and with an increase of large oligomers. It is possible that Hsp27 plays a crucial role in the termination of growth. |
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==References== |
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{{reflist}} |
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==External links== |
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* {{MeshName|HSPB1+protein,+human}} |
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{{Chaperones}} |
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[[Category:Proteins]] |
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[[Category:Heat shock proteins]] |
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[[fr:Hsp27]] |
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Revision as of 05:02, 10 October 2008
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Jeremy Shum sex scandal coverup
I was wondering whether there were any reputable sources that could be quoted in regard to the sex scandal cover-up (http://groups.google.com/group/uk.music.christian/msg/031b64cadce498fd). Apparently, Sony BMG has, like the Brooke Fraser sex scandal, tried to cover everything up again. It seems like the sex video has been entirely removed off the internet.Wrickwareen (talk) 05:02, 10 October 2008 (UTC)
Source of article content
I have checked the article and all the text beyond the introductory paragraph is a cut a paste job from official site's biography. If no one does anything about it in next week, I will remove the text and add a music artist template reducing this article to stub.--Kevin586 15:09, 21 June 2007 (UTC)
Lack of sources in general
I cannot find anywhere on the Internet that Krystal Meyers considers herself "the real rock chick". A citation is needed for Anticonformity and the Christian camp. I also suggest a "Comparison with Avril Lavigne" or "Comparison with other rock chicks" section. --Superkirbyartist (talk) 23:27, 20 November 2007 (UTC)Krystal Roxxxxxxxxxx!!!!!!!
YOU ROX!!!!!!!
your music iz off the chain .!!!! —Preceding unsigned comment added by 67.163.13.2 (talk) 20:20, 14 September 2008 (UTC)