Dataset Information

Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation.

ABSTRACT: Most eukaryotic secretory proteins are cotranslationally translocated through Sec61 into the endoplasmic reticulum (ER). Because these proteins have evolved to fold in the ER, their mistargeting is associated with toxicity. Genetic experiments have implicated the ER heat shock protein 70 (Hsp70) Hspa13/STCH as involved in processing of nascent secretory proteins. Herein, we evaluate the role of Hspa13 in protein import and the maintenance of cellular proteostasis in human cells, primarily using the human embryonic kidney 293T cell line. We find that Hspa13 interacts primarily with the Sec61 translocon and its associated factors. Hspa13 overexpression inhibits translocation of the secreted protein transthyretin, leading to accumulation and aggregation of immature transthyretin in the cytosol. ATPase-inactive mutants of Hspa13 further inhibit translocation and maturation of secretory proteins. While Hspa13 overexpression inhibits cell growth and ER quality control, we demonstrate that HSPA13 knockout destabilizes proteostasis and increases sensitivity to ER disruption. Thus, we propose that Hspa13 regulates import through the translocon to maintain both ER and cytosolic protein homeostasis. The raw mass spectrometry data associated with this article have been deposited in the PRIDE archive and can be accessed at PXD033498.

SUBMITTER: Espinoza MF

PROVIDER: S-EPMC9691929 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation.

Espinoza Mateo F MF Nguyen Khanh K KK Sycks Melody M MM Lyu Ziqi Z Quanrud Guy M GM Montoya Maureen R MR Genereux Joseph C JC

The Journal of biological chemistry 20221014 12

Most eukaryotic secretory proteins are cotranslationally translocated through Sec61 into the endoplasmic reticulum (ER). Because these proteins have evolved to fold in the ER, their mistargeting is associated with toxicity. Genetic experiments have implicated the ER heat shock protein 70 (Hsp70) Hspa13/STCH as involved in processing of nascent secretory proteins. Herein, we evaluate the role of Hspa13 in protein import and the maintenance of cellular proteostasis in human cells, primarily using ...[more]

PMID: 36244454

Similar Datasets

Project description:BackgroundAlthough prostate cancer responds initially to androgen ablation therapies, progression to castration-resistant prostate cancer (CRPC) frequently occurs. Heat shock protein (Hsp) 90 inhibition is a rational therapeutic strategy for CRPC that targets key proteins such as androgen receptor (AR) and protein kinase B (Akt); however, most Hsp90 inhibitors trigger elevation of stress proteins like Hsp27 that confer tumor cell survival and treatment resistance.ObjectiveWe hypothesized that cotargeting the cytoprotective chaperone Hsp27 and Hsp90 would amplify endoplasmic reticulum (ER) stress and treatment-induced cell death in cancer.Design, setting, and participantsInducible and constitutive Hsp27 and other HSPs were measured by real-time reverse transcription-polymerase chain reaction and immunoblot assays. The combinations of OGX-427 with Hsp90 inhibitors were evaluated in vitro for LNCaP cell growth and apoptosis and in vivo in CRPC LNCaP xenograft models.Outcome measurements and statistical analysisTumor volumes were compared using the Kruskal-Wallis test. Overall survival was analyzed using Kaplan-Meier curves, and statistical significance was assessed with the log-rank test.Results and limitationsHsp90 inhibitors induced expression of HSPs in tumor cells and tissues in a dose- and time-dependent manner; in particular, Hsp27 mRNA and protein levels increased threefold. In vitro, OGX-427 synergistically enhanced Hsp90 inhibitor-induced suppression of cell growth and induced apoptosis by 60% as measured by increased sub-G1 fraction and poly(ADP-ribose) polymerase cleavage. These biologic events were accompanied by decreased expression of HSPs, Akt, AR, and prostate-specific antigen, and induction of ER stress markers (cleaved activating transcription factor 6, glucose-regulated protein 78, and DNA-damage-inducible transcript 3). In vivo, OGX-427 potentiated the anticancer effects of Hsp90 inhibitor PF-04929113 (orally, 25mg/kg) to inhibit tumor growth and prolong survival in CRPC LNCaP xenografts.ConclusionsHSP90 inhibitor-mediated induction of Hsp27 expression can be attenuated by OGX-427, resulting in increased ER stress and apoptosis, and synergistic inhibition of CRPC tumor growth.Patient summaryThis study supports the development of targeted strategies using OGX-427 in combination with Hsp90 inhibitors to improve patient outcome in CRPC.

Dataset Information

Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation.

Publications

Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets