The 90-kDa Heat Shock Protein (hsp90) Induces the Condensation of the Chromatin Structure

Csermely, Péter; Kajtár, Judit; Hollósi, Miklós; Oikarinen, Jouko; Somogyi, J.

doi:10.1006/bbrc.1994.2124

Cited by 48 publications

(24 citation statements)

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“…Our observation that NASP-HSP90 complexes occur only in the cytoplasm implies that there is a mechanism to release NASP from the complex. HSP90 can autophosphorylate serine (30) or threonine (23), and this has been proposed to control chaperone binding (31)(32)(33)(34); therefore phosphorylation of HSP90 may regulate tNASP binding (35).…”

Section: Discussionmentioning

confidence: 99%

Association of NASP with HSP90 in Mouse Spermatogenic Cells

Alekseev

Widgren

Richardson

et al. 2005

Journal of Biological Chemistry

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Linker histones (H1s) 1 bind to DNA in the nucleosomes of chromatin and influence the formation of chromatin fibers, gene transcription, nucleosome spacing, chromatin remodeling, and cell cycle progression (1-5). Studies on linker histones in the cell nucleus indicate that there is a constant exchange of H1s with their DNA-binding sites (6, 7) and that H1s not bound to DNA are bound to the histone-binding protein NASP (8). NASP is a histone-binding protein found in all dividing cells in either a somatic/embryo or testis/embryo (tNASP) form (9 -11). Overexpression of tNASP affects progression through the cell cycle, and Alekseev et al. (8) recently postulated that a dynamic equilibrium exists between H1-NASP complexes and H1 bound to DNA. Previous studies on NASP (9) demonstrated that in vivo the somatic linker histones H1a-H1e (see Ref. 12 for mouse histone H1 nomenclature) were co-precipitated with NASP from somatic cell lysates, indicating that NASP is not selective for H1 subtypes.Of the several different subtypes of H1 histones, H1a, b, c, d, and e are found in most cells, whereas H1t is restricted to the testis. H1t is expressed during spermatogenesis, representing as much as 50% of the total H1 histones in pachytene spermatocytes (13-15), and is preceded by tNASP expression in preleptotene spermatocytes. Although their exact function during spermatogenesis is unknown, gene-targeting experiments (16) have shown that the absence of H1t and H1a in double null mice does not compromise spermatogenesis because compensation by H1c, H1d, and H1e most likely maintained normal spermatogenesis despite a reduced H1/nucleosome ratio (16). Under these conditions the major H1 histone binding activity of tNASP could have shifted from H1t to H1c, H1d, and H1e in double null mice. Unfortunately neither the relationship between tNASP, H1t, and other proteins nor the ability of tNASP to transport H1s into the mammalian cell nucleus has been characterized. Therefore we have studied tNASP in spermatogenic cells to understand more about the role of NASP-H1t complexes and now report that H1t binds tNASP in mouse germ cells in a complex in the cytoplasm that contains HSP90, which facilitates the initial loading of linker histones to tNASP. Moreover, tNASP can transport both H1t and somatic linker histones into nuclei. EXPERIMENTAL PROCEDURESAll of the chemicals and reagents used in this study were molecular biology grade. The restriction enzymes were purchased from Roche Applied Science. Purification of plasmid DNA and PCR products were carried out using QIAprep Miniprep and QIAquick PCR purification kits (Qiagen), and sequencing was performed at the University of North Carolina at Chapel Hill automated sequencing facility. Rabbit antihistone H1 (FL-219) polyclonal antiserum and mouse monoclonal IgG 2a anti-HSP90 (F-8) antiserum were purchased from Santa Cruz Biotechnology (Santa Cruz, CA). Anti-H1t antibody was a gift from Dr. M. Meistrich (Department of Experimental Radiation Oncology, M. D. Anderson Cancer Center, University ...

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Section: Discussionmentioning

confidence: 99%

Association of NASP with HSP90 in Mouse Spermatogenic Cells

Alekseev

Widgren

Richardson

et al. 2005

Journal of Biological Chemistry

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“…Interaction between Hsp90 and histone proteins led to the suggestion that Hsp90 may affect chromatin structure and organization (5,6). Importantly, involvement of Hsp90 in the disassembly of transcriptional regulatory complexes (2) revealed a potential molecular link between Hsp90 and gene regulation at the chromatin level.…”

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confidence: 99%

Trithorax requires Hsp90 for maintenance of active chromatin at sites of gene expression

Tariq

Nussbaumer

Chen

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

115

133

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“…Among other enzymes, DNase I (-31 kDa) has recently been proposed to be involved in this process [33,34]. Furthermore, hsp 90 has been reported to induce the condensation of the chromatin structure [35], which is a biochemical hallmark of apoptosis. mate exposure in basal solution as well as in low sodium-chloride solution, we observed a specific increase of [3sS]-methionine incorporation in some proteins among which calreticuline and protein numbered 3 (68 kDa, p i 5) whereas [35S]methionine incorporation in calmodulin was dramatically reduced (Table 1 and Fig.…”

Section: Discussionmentioning

confidence: 99%

Use of two‐dimensional gel electrophoresis to characterize protein synthesis during neuronal death in cerebellar culture

1996

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Two-dimensional gel electrophoresis was performed to further investigate the biochemical changes in protein synthesis observed in two neuronal death models, induced respectively by cytosine arabinoside and glutamate. These drugs induced, respectively, apoptotic and necrotic types of cell death in cerebellar cultures, as previously reported. Most of the proteins showed decreased labeling after toxic exposure, as expected, but some polypeptides showed increased labeling or appeared to be newly synthesized. The identification of these polypeptides and their implication in neuronal death are discussed.

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The 90-kDa Heat Shock Protein (hsp90) Induces the Condensation of the Chromatin Structure

Cited by 48 publications

References 0 publications

Association of NASP with HSP90 in Mouse Spermatogenic Cells

Association of NASP with HSP90 in Mouse Spermatogenic Cells

Trithorax requires Hsp90 for maintenance of active chromatin at sites of gene expression

Use of two‐dimensional gel electrophoresis to characterize protein synthesis during neuronal death in cerebellar culture

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