scholarly journals Human protein phosphatase 5 dissociates from heat-shock proteins and is proteolytically activated in response to arachidonic acid and the microtubule-depolymerizing drug nocodazole

2004 ◽  
Vol 385 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Tamás ZEKE ◽  
Nick MORRICE ◽  
Cristina VÁZQUEZ-MARTIN ◽  
Patricia T. W. COHEN
Keyword(s):  
Arachidonic Acid ◽  
Heat Shock ◽  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Nuclear Localization Sequence ◽  
Protein Phosphatase 5 ◽  
C Terminus ◽  
Localization Sequence ◽  
Shock Proteins

Ppp5 (protein phosphatase 5) is a serine/threonine protein phosphatase that has been conserved throughout eukaryotic evolution. In mammalian cells, FLAG-tagged Ppp5 and endogenous Ppp5 are found to interact with endogenous Hsp (heat-shock protein) 70, as well as Hsp90. Incubation of cells with arachidonic acid or the microtubule-depolymerizing agent, nocodazole, causes loss of interaction of Hsp70 and Hsp90 with FLAG-tagged Ppp5 and increase of Ppp5 activity. In response to the same treatments, endogenous Ppp5 undergoes proteolytic cleavage of the N- and C-termini, with the subsequent appearance of high-molecular-mass species. The results indicate that Ppp5 is activated by proteolysis on dissociation from Hsps, and is destroyed via the proteasome after ubiquitination. Cleavage at the C-terminus removes a nuclear localization sequence, allowing these active cleaved forms of Ppp5 to translocate to the cytoplasm. The response of Ppp5 to arachidonic acid and nocodazole suggests that Ppp5 may be required for stress-related processes that can sometimes cause cell-cycle arrest, and leads to the first description for in vivo regulation of Ppp5 activity.

scholarly journals Interaction between DNA-damage protein GADD34 and a new member of the Hsp40 family of heat shock proteins that is induced by a DNA-damaging reagent

2000 ◽  
Vol 352 (3) ◽  
pp. 795-800 ◽  
Author(s):  
Tadao HASEGAWA ◽  
Hengyi XIAO ◽  
Fumiyasu HAMAJIMA ◽  
Ken-ichi ISOBE
Keyword(s):  
Dna Damage ◽  
Heat Shock ◽  
Cultured Cells ◽  
Similar Region ◽  
C Terminus ◽  
Mouse Tissues ◽  
Time Courses ◽  
Shock Proteins ◽  
Two Hybrid

GADD34 is one of a subset of proteins induced after DNA damage or cell growth arrest. To examine the function of GADD34, we used the yeast two-hybrid system to clone the protein that interacts with murine GADD34. As bait we used the product of the partial GADD34 cDNA, including the regions rich in proline, glutamic acid, serine and threonine (PEST) and γ134.5 regions. A cDNA clone, named GAHSP40, which is a mouse DnaJ family protein with a high similarity to human HLJ1 was cloned. The interaction between GADD34 and GAHSP40 in cultured cells was confirmed by a co-immunoprecipitation experiment and in NIH 3T3 cells by two-hybrid analysis in vivo. For binding of the two proteins, the γ134.5-similar region of GADD34 was necessary; however, the PEST region was also involved and the C-terminus of GAHSP40, but not the J-domain, was important. GAHSP40 was detected in all mouse tissues examined, but a different transcript was found in the testis. Both GADD34 mRNA and GAHSP40 mRNA were significantly elevated by treatment with methyl methanesulphonate, although the time courses were different. In addition, both GAHSP40 and GADD34 mRNA were induced by heat shock.

Principles of chaperone-mediated protein folding

1995 ◽  
Vol 348 (1323) ◽  
pp. 107-112 ◽  
Keyword(s):  
Protein Folding ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Molecular Chaperones ◽  
Cellular Protein ◽  
Chaperone Proteins ◽  
Shock Proteins ◽  
Polypeptide Chains

The recent discovery of molecular chaperones and their functions has changed dramatically our view of the processes underlying the folding of proteins in vivo . Rather than folding spontaneously, most newly synthesized polypeptide chains seem to acquire their native conformations in a reaction mediated by chaperone proteins. Different classes of molecular chaperones, such as the members of the Hsp70 and Hsp60 families of heat-shock proteins, cooperate in a coordinated pathway of cellular protein folding.

scholarly journals Cross-priming of minor histocompatibility antigen-specific cytotoxic T cells upon immunization with the heat shock protein gp96.

1995 ◽  
Vol 182 (3) ◽  
pp. 885-889 ◽  
Author(s):  
D Arnold ◽  
S Faath ◽  
H Rammensee ◽  
H Schild
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Protein ◽  
Tumor Cells ◽  
Mhc Class I ◽  
Donor Cell ◽  
Class I ◽  
Heat Shock Protein Gp96 ◽  
Shock Proteins

Vaccination of mice with heat shock proteins isolated from tumor cells induces immunity to subsequent challenge with those tumor cells the heat shock protein was isolated from but not with other tumor cells (Udono, H., and P.K. Srivastava. 1994. J. Immunol. 152:5398-5403). The specificity of this immune response is caused by tumor-derived peptides bound to the heat shock proteins (Udono., H., and P.K. Srivastava. 1993. J. Exp. Med. 178:1391-1396). Our experiments show that a single immunization with the heat shock protein gp96 isolated from beta-galactosidase (beta-gal) expressing P815 cells (of DBA/2 origin) induces cytotoxic T lymphocytes (CTLs) specific for beta-gal, in addition to minor H antigens expressed by these cells. CTLs can be induced in mice that are major histocompatibility complex (MHC) identical to the gp96 donor cells (H-2d) as well as in mice with a different MHC (H-2b). Thus gp96 is able to induce "cross priming" (Matzinger, P., and M.J. Bevan. 1977. Cell. Immunol. 33:92-100), indicating that gp96-associated peptides are not limited to the MHC class I ligands of the gp96 donor cell. Our data confirm the notion that samples of all cellular antigens presentable by MHC class I molecules are represented by peptides associated with gp96 molecules of that cell, even if the fitting MHC molecule is not expressed. In addition, we extend previous reports on the in vivo immunogenicity of peptides associated gp96 molecules to two new groups of antigens, minor H antigens, and proteins expressed in the cytosol.

scholarly journals The Effect of Oxidized Dopamine on the Structure and Molecular Chaperone Function of the Small Heat-Shock Proteins, αB-Crystallin and Hsp27

2021 ◽  
Vol 22 (7) ◽  
pp. 3700
Author(s):  
Junna Hayashi ◽  
Jennifer Ton ◽  
Sparsh Negi ◽  
Daniel E. K. M. Stephens ◽  
Dean L. Pountney ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Aggregation ◽  
Molecular Chaperone ◽  
Cross Linking ◽  
Αb Crystallin ◽  
The Cross ◽  
Shock Proteins ◽  
And Function

Oxidation of the neurotransmitter, dopamine (DA), is a pathological hallmark of Parkinson’s disease (PD). Oxidized DA forms adducts with proteins which can alter their functionality. αB-crystallin and Hsp27 are intracellular, small heat-shock molecular chaperone proteins (sHsps) which form the first line of defense to prevent protein aggregation under conditions of cellular stress. In vitro, the effects of oxidized DA on the structure and function of αB-crystallin and Hsp27 were investigated. Oxidized DA promoted the cross-linking of αB-crystallin and Hsp27 to form well-defined dimer, trimer, tetramer, etc., species, as monitored by SDS-PAGE. Lysine residues were involved in the cross-links. The secondary structure of the sHsps was not altered significantly upon cross-linking with oxidized DA but their oligomeric size was increased. When modified with a molar equivalent of DA, sHsp chaperone functionality was largely retained in preventing both amorphous and amyloid fibrillar aggregation, including fibril formation of mutant (A53T) α-synuclein, a protein whose aggregation is associated with autosomal PD. In the main, higher levels of sHsp modification with DA led to a reduction in chaperone effectiveness. In vivo, DA is sequestered into acidic vesicles to prevent its oxidation and, intracellularly, oxidation is minimized by mM levels of the antioxidant, glutathione. In vitro, acidic pH and glutathione prevented the formation of oxidized DA-induced cross-linking of the sHsps. Oxidized DA-modified αB-crystallin and Hsp27 were not cytotoxic. In a cellular context, retention of significant chaperone functionality by mildly oxidized DA-modified sHsps would contribute to proteostasis by preventing protein aggregation (particularly of α-synuclein) that is associated with PD.

scholarly journals Molecular chaperones and heat shock proteins in atherosclerosis

2012 ◽  
Vol 302 (3) ◽  
pp. H506-H514 ◽  
Author(s):  
Qingbo Xu ◽  
Bernhard Metzler ◽  
Marjan Jahangiri ◽  
Kaushik Mandal
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Molecular Chaperones ◽  
Mammalian Cells ◽  
Vessel Wall ◽  
Protective Role ◽  
Research Field ◽  
Stressed Cells ◽  
Shock Proteins ◽  
Prevention Of Atherosclerosis

In response to stress stimuli, mammalian cells activate an ancient signaling pathway leading to the transient expression of heat shock proteins (HSPs). HSPs are a family of proteins serving as molecular chaperones that prevent the formation of nonspecific protein aggregates and assist proteins in the acquisition of their native structures. Physiologically, HSPs play a protective role in the homeostasis of the vessel wall but have an impact on immunoinflammatory processes in pathological conditions involved in the development of atherosclerosis. For instance, some members of HSPs have been shown to have immunoregulatory properties and modification of innate and adaptive response to HSPs, and can protect the vessel wall from the disease. On the other hand, a high degree of sequence homology between microbial and mammalian HSPs, due to evolutionary conservation, carries a risk of misdirected autoimmunity against HSPs expressed on the stressed cells of vascular endothelium. Furthermore, HSPs and anti-HSP antibodies have been shown to elicit production of proinflammatory cytokines. Potential therapeutic use of HSP in prevention of atherosclerosis involves achieving optimal balance between protective and immunogenic effects of HSPs and in the progress of research on vaccination. In this review, we update the progress of studies on HSPs and the integrity of the vessel wall, discuss the mechanism by which HSPs exert their role in the disease development, and highlight the potential clinic translation in the research field.

scholarly journals Identification and characterization of molecular interactions between mortalin/mtHsp70 and HSP60

2005 ◽  
Vol 391 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Renu Wadhwa ◽  
Syuichi Takano ◽  
Kamaljit Kaur ◽  
Satoshi Aida ◽  
Tomoko Yaguchi ◽  
...  
Keyword(s):  
Heat Shock ◽  
Molecular Interactions ◽  
Heat Shock Protein 60 ◽  
Hsp60 Expression ◽  
Mitochondrial Hsp70 ◽  
Shock Proteins ◽  
First Time

Mortalin/mtHsp70 (mitochondrial Hsp70) and HSP60 (heat-shock protein 60) are heat-shock proteins that reside in multiple subcellular compartments, with mitochondria being the predominant one. In the present study, we demonstrate that the two proteins interact both in vivo and in vitro, and that the N-terminal region of mortalin is involved in these interactions. Suppression of HSP60 expression by shRNA (short hairpin RNA) plasmids caused the growth arrest of cancer cells similar to that obtained by suppression of mortalin expression by ribozymes. An overexpression of mortalin, but not of HSP60, extended the in vitro lifespan of normal fibroblasts (TIG-1). Taken together, this study for the first time delineates: (i) molecular interactions of HSP60 with mortalin; (ii) their co- and exclusive localizations in vivo; (iii) their involvement in tumorigenesis; and (iv) their functional distinction in pathways involved in senescence.

scholarly journals Characterization of constitutive HSF2 DNA-binding activity in mouse embryonal carcinoma cells

1994 ◽  
Vol 14 (8) ◽  
pp. 5309-5317
Author(s):  
S P Murphy ◽  
J J Gorzowski ◽  
K D Sarge ◽  
B Phillips
Keyword(s):  
Transcription Factors ◽  
Heat Shock ◽  
Dna Binding ◽  
Mammalian Cells ◽  
Embryonal Carcinoma ◽  
Embryonic Stem ◽  
Binding Activity ◽  
Hsp70 Promoter ◽  
Ec Cells

Two distinct murine heat shock transcription factors, HSF1 and HSF2, have been identified. HSF1 mediates the transcriptional activation of heat shock genes in response to environmental stress, while the function of HSF2 is not understood. Both factors can bind to heat shock elements (HSEs) but are maintained in a non-DNA-binding state under normal growth conditions. Mouse embryonal carcinoma (EC) cells are the only mammalian cells known to exhibit HSE-binding activity, as determined by gel shift assays, even when maintained at normal physiological temperatures. We demonstrate here that the constitutive HSE-binding activity present in F9 and PCC4.aza.R1 EC cells, as well as a similar activity found to be present in mouse embryonic stem cells, is composed predominantly of HSF2. HSF2 in F9 EC cells is trimerized and is present at higher levels than in a variety of nonembryonal cell lines, suggesting a correlation of these properties with constitutive HSE-binding activity. Surprisingly, transcription run-on assays suggest that HSF2 in unstressed EC cells does not stimulate transcription of two putative target genes, hsp70 and hsp86. Genomic footprinting analysis indicates that HSF2 is not bound in vivo to the HSE of the hsp70 promoter in unstressed F9 EC cells, although HSF2 is present in the nucleus and the promoter is accessible to other transcription factors and to HSF1 following heat shock. Thus trimerization and nuclear localization of HSF2 do not appear to be sufficient for in vivo binding of HSF2 to the HSE of the hsp70 promoter in unstressed F9 EC cells.

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