The 26S Proteasome Function and Hsp90 Activity Involved in the Regulation of HsfA2 Expression in Response to Oxidative Stress

Nishizawa‐Yokoi, Ayako; Tainaka, Hitoshi; Yoshida, Eriko; Tamoi, Masahiro; Yabuta, Yukinori; Shigeoka, Shigeru

doi:10.1093/pcp/pcq015

Cited by 59 publications

(61 citation statements)

References 80 publications

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“…Figure 8C, lanes 5 and 10). Consistently, polyubiquitin-conjugated proteins accumulated upon addition of GDA, PSI, or LLM (see Supplemental Figure 3 online), which parallels previous observations while treating plant cells with GDA or the proteasome inhibitor MG132 (Kurepa et al, 2008;Nishizawa-Yokoi et al, 2010). Although the accumulation of HsfB1 was comparable in the presence of all three inhibitors at the concentrations applied (Figure 8), the accumulation of polyubiquitin-conjugated proteins was more pronounced for PSI and LLM (see Supplemental Figure 3 online).…”

Section: Hsp90 Acts In Targeting Hsfb1 Protein For Proteasomal Degradsupporting

confidence: 86%

Crosstalk between Hsp90 and Hsp70 Chaperones and Heat Stress Transcription Factors in Tomato

Hahn¹,

Bublak²,

Schleiff³

et al. 2011

The Plant Cell

299

264

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Heat stress transcription factors (Hsfs) regulate gene expression in response to environmental stress. The Hsf network in plants is controlled at the transcriptional level by cooperation of distinct Hsf members and by interaction with chaperones. We found two general mechanisms of Hsf regulation by chaperones while analyzing the three major Hsfs, A1, A2, and B1, in tomato (Solanum lycopersicum). First, Hsp70 and Hsp90 regulate Hsf function by direct interactions. Hsp70 represses the activity of HsfA1, including its DNA binding, and the coactivator function of HsfB1 in the complex with HsfA2, while the DNA binding activity of HsfB1 is stimulated by Hsp90. Second, Hsp90 affects the abundance of HsfA2 and HsfB1 by modulating hsfA2 transcript degradation involved in regulation of the timing of HsfA2 synthesis. By contrast, HsfB1 binding to Hsp90 and to DNA are prerequisites for targeting this Hsf for proteasomal degradation, which also depends on a sequence element in its carboxyl-terminal domain. Thus, HsfB1 represents an Hsp90 client protein that, by interacting with the chaperone, is targeted for, rather than protected from, degradation. Based on these findings, we propose a versatile regulatory regime involving Hsp90, Hsp70, and the three Hsfs in the control of heat stress response.

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Section: Hsp90 Acts In Targeting Hsfb1 Protein For Proteasomal Degradsupporting

confidence: 86%

Crosstalk between Hsp90 and Hsp70 Chaperones and Heat Stress Transcription Factors in Tomato

Hahn¹,

Bublak²,

Schleiff³

et al. 2011

The Plant Cell

299

264

View full text Add to dashboard Cite

show abstract

“…In plants, loss of function of the 26S proteasome leads to cell death (CD) and to the release of ROS (Kim et al, 2003). GDA-induced HSP90 inhibition causes the disruption of the 26S proteasome and the loss of its protease activity (Nishizawa-Yokoi et al, 2010). HSP90 inactivation also leads to a decrease in the degradation of the TYLCV protein V2 by the 26S proteasome (Moshe et al, 2016).…”

Section: Tylcv Interactions With Plant Host and Insect Vector Heat Shmentioning

confidence: 99%

The Involvement of Heat Shock Proteins in the Establishment of Tomato Yellow Leaf Curl Virus Infection

Gorovits

Czosnek

2017

Front. Plant Sci.

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Tomato yellow leaf curl virus (TYLCV), a begomovirus, induces protein aggregation in infected tomatoes and in its whitefly vector Bemisia tabaci. The interactions between TYLCV and HSP70 and HSP90 in plants and vectors are necessity for virus infection to proceed. In infected host cells, HSP70 and HSP90 are redistributed from a soluble to an aggregated state. These aggregates contain, together with viral DNA/proteins and virions, HSPs and components of the protein quality control system such as ubiquitin, 26S proteasome subunits, and the autophagy protein ATG8. TYLCV CP can form complexes with HSPs in tomato and whitefly. Nonetheless, HSP70 and HSP90 play different roles in the viral cell cycle in the plant host. In the infected host cell, HSP70, but not HSP90, participates in the translocation of CP from the cytoplasm into the nucleus. Viral amounts decrease when HSP70 is inhibited, but increase when HSP90 is downregulated. In the whitefly vector, HSP70 impairs the circulative transmission of TYLCV; its inhibition increases transmission. Hence, the efficiency of virus acquisition by whiteflies depends on the functionality of both plant chaperones and their cross-talk with other protein mechanisms controlling virus-induced aggregation.

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“…The inactivation of HSP90 increased the expression of HSFA2 and consequently, the expression of HSFA2-regulated genes, as shown in Arabidopsis cell cultures (Nishizawa-Yokoi et al 2010) and in tomato leaves . To increase the basal HSFA2 levels, the plant tissues were subjected to heat shock (HS).…”

Section: Effect Of Individual Tylcv Genes On the Accumulation Of Hsfamentioning

confidence: 70%

“…Inactivation of the HSP90 machinery reduces the 26S proteasome activity and, consequently, the UPS function in plant cells (Nishizawa-Yokoi et al 2010). We have shown previously that in Hsp90-silenced tomatoes, ubiquitinated proteins and the core 20S proteasome accumulated ), pointing to UPS inactivation (Yamano et al 2008).…”

Section: Ubiquitin-proteasome System (Ups) Patterns In Tomatoes Contamentioning

confidence: 95%

“…The inactivation of the HSP90-dependent ubiquitin-proteasome system (UPS) was alleviated in TYLCV-infected plants. In parallel, the activation of the transcription factor HSFB1, and of HSFA2 by itself and together with the HSFA2-regulated genes Hsp17 (encoding the small HSP17) and Apx1/2 (encoding the ascorbate peroxidases 1 and 2 (Nishizawa-Yokoi et al 2010), was appropriately impaired in virus-infected cells. Because of the downregulation of the plant stress response, TYLCV can accumulate and cause disease in tomato plants.…”

Section: Introductionmentioning

confidence: 99%

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The six Tomato yellow leaf curl virus genes expressed individually in tomato induce different levels of plant stress response attenuation

Gorovits

Moshe

Amrani

et al. 2017

Cell Stress and Chaperones

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Tomato yellow leaf curl virus (TYLCV) is a begomovirus infecting tomato plants worldwide. TYLCV needs a healthy host environment to ensure a successful infection cycle for long periods. Hence, TYLCV restrains its destructive effect and induces neither a hypersensitive response nor cell death in infected tomatoes. On the contrary, TYLCV counteracts cell death induced by other factors, such as inactivation of HSP90 functionality. Suppression of plant death is associated with the inhibition of the ubiquitin 26S proteasome degradation and with a deactivation of the heat shock transcription factor HSFA2 pathways (including decreased HSP17 levels). The goal of the current study was to find if the individual TYLCV genes were capable of suppressing HSP90-dependent death and HSFA2 deactivation. The expression of C2 (C3 and CP to a lesser extent) caused a decrease in the severity of death phenotypes, while the expression of V2 (C1 and C4 to a lesser extent) strengthened cell death. However, C2 or V2 markedly affected stress response under conditions of viral infection. The downregulation of HSFA2 signaling, initiated by the expression of C1 and V2, was detected in the absence of virus infection, but was enhanced in infected plants, while CP and C4 mitigated HSFA2 levels only in the infected tomatoes. The dependence of analyzed plant stress response suppression on the interaction of the expressed genes with the environment created by the whole virus infection was more pronounced than on the expression of individual TYLCV genes.

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The 26S Proteasome Function and Hsp90 Activity Involved in the Regulation of HsfA2 Expression in Response to Oxidative Stress

Cited by 59 publications

References 80 publications

Crosstalk between Hsp90 and Hsp70 Chaperones and Heat Stress Transcription Factors in Tomato

Crosstalk between Hsp90 and Hsp70 Chaperones and Heat Stress Transcription Factors in Tomato

The Involvement of Heat Shock Proteins in the Establishment of Tomato Yellow Leaf Curl Virus Infection

The six Tomato yellow leaf curl virus genes expressed individually in tomato induce different levels of plant stress response attenuation

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