scholarly journals Do ARG1 and ARL2 form an actin-based gravity-signaling chaperone complex in root statocytes?

2008 ◽  
Vol 3 (9) ◽  
pp. 650-653 ◽  
Author(s):  
Benjamin Harrison ◽  
Patrick H. Masson
Keyword(s):  
Chaperone Complex ◽  
Root Statocytes

scholarly journals VTC4 Polyphosphate Polymerase Knockout Increases Stress Resistance of Saccharomyces cerevisiae Cells

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 487
Author(s):  
Alexander Tomashevsky ◽  
Ekaterina Kulakovskaya ◽  
Ludmila Trilisenko ◽  
Ivan V. Kulakovskiy ◽  
Tatiana Kulakovskaya ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heavy Metal ◽  
Stress Response ◽  
Stress Resistance ◽  
Alkaline Stress ◽  
Inorganic Polyphosphate ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Elevated Expression ◽  
Chaperone Complex

Inorganic polyphosphate (polyP) is an important factor of alkaline, heavy metal, and oxidative stress resistance in microbial cells. In yeast, polyP is synthesized by Vtc4, a subunit of the vacuole transporter chaperone complex. Here, we report reduced but reliably detectable amounts of acid-soluble and acid-insoluble polyPs in the Δvtc4 strain of Saccharomyces cerevisiae, reaching 10% and 20% of the respective levels of the wild-type strain. The Δvtc4 strain has decreased resistance to alkaline stress but, unexpectedly, increased resistance to oxidation and heavy metal excess. We suggest that increased resistance is achieved through elevated expression of DDR2, which is implicated in stress response, and reduced expression of PHO84 encoding a phosphate and divalent metal transporter. The decreased Mg2+-dependent phosphate accumulation in Δvtc4 cells is consistent with reduced expression of PHO84. We discuss a possible role that polyP level plays in cellular signaling of stress response mobilization in yeast.

scholarly journals The Hsp90 Chaperone Complex Regulates GDI-dependent Rab Recycling

2006 ◽  
Vol 17 (8) ◽  
pp. 3494-3507 ◽  
Author(s):  
Christine Y. Chen ◽  
William E. Balch
Keyword(s):  
Rab Gtpase ◽  
Rab Gtpases ◽  
Coding System ◽  
Golgi Transport ◽  
Guanine Nucleotide Dissociation Inhibitor ◽  
Hsp90 Activity ◽  
Hsp90 Chaperone ◽  
Chaperone Complex ◽  
Hsp 90 ◽  
Synaptic Vesicle Fusion

Rab GTPase regulated hubs provide a framework for an integrated coding system, the membrome network, that controls the dynamics of the specialized exocytic and endocytic membrane architectures found in eukaryotic cells. Herein, we report that Rab recycling in the early exocytic pathways involves the heat-shock protein (Hsp)90 chaperone system. We find that Hsp90 forms a complex with guanine nucleotide dissociation inhibitor (GDI) to direct recycling of the client substrate Rab1 required for endoplasmic reticulum (ER)-to-Golgi transport. ER-to-Golgi traffic is inhibited by the Hsp90-specific inhibitors geldanamycin (GA), 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG), and radicicol. Hsp90 activity is required to form a functional GDI complex to retrieve Rab1 from the membrane. Moreover, we find that Hsp90 is essential for Rab1-dependent Golgi assembly. The observation that the highly divergent Rab GTPases Rab1 involved in ER-to-Golgi transport and Rab3A involved in synaptic vesicle fusion require Hsp90 for retrieval from membranes lead us to now propose that the Hsp90 chaperone system may function as a general regulator for Rab GTPase recycling in exocytic and endocytic trafficking pathways involved in cell signaling and proliferation.

scholarly journals Deciphering molecular details of the RAC–ribosome interaction by EPR spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sandra J. Fries ◽  
Theresa S. Braun ◽  
Christoph Globisch ◽  
Christine Peter ◽  
Malte Drescher ◽  
...  
Keyword(s):  
Protein Folding ◽  
Epr Spectroscopy ◽  
De Novo ◽  
Contact Point ◽  
Ribosomal Subunit ◽  
Paramagnetic Resonance ◽  
40S Ribosomal Subunit ◽  
Site Directed Spin Labeling ◽  
Α Helix ◽  
Chaperone Complex

AbstractThe eukaryotic ribosome-associated complex (RAC) plays a significant role in de novo protein folding. Its unique interaction with the ribosome, comprising contacts to both ribosomal subunits, suggests a RAC-mediated coordination between translation elongation and co-translational protein folding. Here, we apply electron paramagnetic resonance (EPR) spectroscopy combined with site-directed spin labeling (SDSL) to gain deeper insights into a RAC–ribosome contact affecting translational accuracy. We identified a local contact point of RAC to the ribosome. The data provide the first experimental evidence for the existence of a four-helix bundle as well as a long α-helix in full-length RAC, in solution as well as on the ribosome. Additionally, we complemented the structural picture of the region mediating this functionally important contact on the 40S ribosomal subunit. In sum, this study constitutes the first application of SDSL-EPR spectroscopy to elucidate the molecular details of the interaction between the 3.3 MDa translation machinery and a chaperone complex.

scholarly journals A Genome-Wide Screen Reveals a Role for the HIR Histone Chaperone Complex in Preventing Mislocalization of Budding Yeast CENP-A

Genetics ◽  
2018 ◽  
Vol 210 (1) ◽  
pp. 203-218 ◽  
Author(s):  
Sultan Ciftci-Yilmaz ◽  
Wei-Chun Au ◽  
Prashant K. Mishra ◽  
Jessica R. Eisenstatt ◽  
Joy Chang ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Histone Chaperone ◽  
Genome Wide ◽  
A Genome ◽  
Chaperone Complex

scholarly journals Crystal structure of an Hsp90–nucleotide–p23/Sba1 closed chaperone complex

Nature ◽  
2006 ◽  
Vol 440 (7087) ◽  
pp. 1013-1017 ◽  
Author(s):  
Maruf M. U. Ali ◽  
S. Mark Roe ◽  
Cara K. Vaughan ◽  
Phillipe Meyer ◽  
Barry Panaretou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chaperone Complex

scholarly journals Observation of the noncovalent assembly and disassembly pathways of the chaperone complex MtGimC by mass spectrometry

2000 ◽  
Vol 97 (26) ◽  
pp. 14151-14155 ◽  
Author(s):  
M. Fandrich ◽  
M. A. Tito ◽  
M. R. Leroux ◽  
A. A. Rostom ◽  
F. U. Hartl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chaperone Complex

scholarly journals FKBP51 Promotes Assembly of the Hsp90 Chaperone Complex and Regulates Androgen Receptor Signaling in Prostate Cancer Cells

2010 ◽  
Vol 30 (5) ◽  
pp. 1243-1253 ◽  
Author(s):  
Li Ni ◽  
Chun-Song Yang ◽  
Daniel Gioeli ◽  
Henry Frierson ◽  
David O. Toft ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Feedback Loop ◽  
Critical Role ◽  
Prostate Cancer Cells ◽  
Androgen Receptor Signaling ◽  
Hsp90 Chaperone ◽  
Chaperone Complex ◽  
Androgen Binding

ABSTRACT Prostate cancer progression to the androgen-independent (AI) state involves acquisition of pathways that allow tumor growth under low-androgen conditions. We hypothesized that expression of molecular chaperones that modulate androgen binding to AR might be altered in prostate cancer and contribute to progression to the AI state. Here, we report that the Hsp90 cochaperone FKBP51 is upregulated in LAPC-4 AI tumors grown in castrated mice and describe a molecular mechanism by which FKBP51 regulates AR activity. Using recombinant proteins, we show that FKBP51 stimulates recruitment of the cochaperone p23 to the ATP-bound form of Hsp90, forming an FKBP51-Hsp90-p23 superchaperone complex. In cells, FKBP51 expression promotes superchaperone complex association with AR and increases the number of AR molecules that undergo androgen binding. FKBP51 stimulates androgen-dependent transcription and cell growth, and FKBP51 is part of a positive feedback loop that is regulated by AR and androgen. Finally, depleting FKBP51 levels by short hairpin RNA reduces the transcript levels of genes regulated by AR and androgen. Because the superchaperone complex plays a critical role in determining the ligand-binding competence and transcription function of AR, it provides an attractive target for inhibiting AR activity in prostate cancer cells.

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