Browse
Submit Data
Databases
API
Help

Dataset Information

9 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Phosphorylation in the Charged Linker Modulates Interactions and Secretion of Hsp90β.

ABSTRACT: Hsp90β is a major chaperone involved in numerous cellular processes. Hundreds of client proteins depend on Hsp90β for proper folding and/or activity. Regulation of Hsp90β is critical to coordinate its tasks and is mediated by several post-translational modifications. Here, we focus on two phosphorylation sites located in the charged linker region of human Hsp90β, Ser226 and Ser255, which have been frequently reported but whose function remains unclear. Targeted measurements by mass spectrometry indicated that intracellular Hsp90β is highly phosphorylated on both sites (>90%). The level of phosphorylation was unaffected by various stresses (e.g., heat shock, inhibition with drugs) that impact Hsp90β activity. Mutating the two serines to alanines increased the amount of proteins interacting with Hsp90β globally and increased the sensitivity to tryptic cleavage in the C-terminal domain. Further investigation revealed that phosphorylation on Ser255 and to a lesser extent on Ser226 is decreased in the conditioned medium of cultured K562 cells, and that a non-phosphorylatable double alanine mutant was secreted more efficiently than the wild type. Overall, our results show that phosphorylation events in the charged linker regulate both the interactions of Hsp90β and its secretion, through changes in the conformation of the chaperone.

SUBMITTER: Weidenauer L

PROVIDER: S-EPMC8304327 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

The Charged Linker Modulates the Conformations and Molecular Interactions of Hsp90.

Project description:The molecular chaperone Hsp90 supports the functional activity of specific substrate proteins (clients). For client processing, the Hsp90 dimer undergoes a series of ATP-driven conformational rearrangements. Flexible linkers connecting the three domains of Hsp90 are crucial to enable dynamic arrangements. The long charged linker connecting the N-terminal (NTD) and middle (MD) domains exhibits additional functions in vitro and in vivo. The structural basis for these functions remains unclear. Here, we characterize the conformation and dynamics of the linker and NTD-MD domain interactions by NMR spectroscopy. Our results reveal two regions in the linker that are dynamic and exhibit secondary structure conformation. We show that these regions mediate transient interactions with strand β8 of the NTD. As a consequence, this strand detaches and exposes a hydrophobic surface patch, which enables binding to the p53 client. We propose that the charged linker plays an important regulatory role by coupling the Hsp90 NTD-MD arrangement with the accessibility of a client binding site on the NTD.

| S-EPMC8048802 | biostudies-literature

Phosphorylation of Hsp90β on serine residues in the charged linker modulates binding to interacting proteins and has implications for overall Hsp90β conformation (Occupancy and phospho-modulation data)

Project description:Human Hsp90β is constitutively phosphorylated in vivo on two serine residues in the charged linker region, S226 and S255. We developed a targeted method to measure the phosphorylation occupancy (the extent of phosphorylation) of both phosphosites in a range of cultured cell lines and consistently found high occupancy (>90%) in the cytoplasm and nucleus. However, we found decreased phosphorylation, especially for S255, in Hsp90β purified from the conditioned medium of cultured K562 cells. In addition, we investigated if various cell growth conditions known to impact Hsp90β activity had an effect on the phosphorylation status of S226 and S255, but none of the conditions tested (e.g. heat shock, Hsp90β inhibition) resulted in an alteration of S226 and S255 phosphorylation.

2021-07-07 | PXD025888 | Pride

Phosphorylation of Hsp90 on serine residues in the charged linker modulates binding to interacting proteins and has implications for overall Hsp90β conformation

Project description:Serine residues in the charged linker region of human Hsp90beta are highly phoshporylated in vivo. Mutation of these residues to alanines resulted in altered binding of many Hsp90beta interactors. This project contains the data and searches related to co-immunoprecipitation experiments with wild-type and mutant Hsp90beta, as well as input.

2021-07-07 | PXD025873 | Pride

Phosphorylation of Hsp90 on serine residues in the charged linker modulates binding to interacting proteins and has implications for overall Hsp90β conformation (limited proteolysis experiment)

Project description:The charged linker region in Hsp90 has been shown to be important for Hsp90 function and global conformation. In humans, two serines located in the charged linker region are constitutively phosphorylated in vivo. In order to gain knowledge on the possible effect of these phosphorylation sites on Hsp90 global conformation, we purified a human Hsp90β mutant where both serines are mutated to alanines, and used limited proteolysis to study the “proteolytic” fingerprint of our mutant and the wild-type, phosphorylated Hsp90β. We observed that serine to alanine mutation resulted in increased tryptic cleavage in the C-domain of Hsp90β.

2021-07-07 | PXD025878 | Pride

Charged linker sequence modulates eukaryotic heat shock protein 90 (Hsp90) chaperone activity.

Project description:Hsp90 is an essential and highly conserved modular molecular chaperone whose N and middle domains are separated by a disordered region termed the charged linker. Although its importance has been previously disregarded, because a minimal linker length is sufficient for Hsp90 activity, the evolutionary persistence of extensive charged linkers of divergent sequence in Hsp90 proteins of most eukaryotes remains unexplained. To examine this question further, we introduced human and plasmodium native and length-matched artificial linkers into yeast Hsp90. After evaluating ATPase activity and biophysical characteristics in vitro, and chaperone function in vivo, we conclude that linker sequence affects Hsp90 function, cochaperone interaction, and conformation. We propose that the charged linker, in addition to providing the flexibility necessary for Hsp90 domain rearrangements--likely its original purpose--has evolved in eukaryotes to serve as a rheostat for the Hsp90 chaperone machine.

| S-EPMC3287002 | biostudies-literature

The charged linker of the molecular chaperone Hsp90 modulates domain contacts and biological function.

Project description:The heat shock protein 90 (Hsp90) is a dimeric molecular chaperone essential in numerous cellular processes. Its three domains (N, M, and C) are connected via linkers that allow the rearrangement of domains during Hsp90's chaperone cycle. A unique linker, called charged linker (CL), connects the N- and M-domain of Hsp90. We used an integrated approach, combining single-molecule techniques and biochemical and in vivo methods, to study the unresolved structure and function of this region. Here we show that the CL facilitates intramolecular rearrangements on the milliseconds timescale between a state in which the N-domain is docked to the M-domain and a state in which the N-domain is more flexible. The docked conformation is stabilized by 1.1 kBT (2.7 kJ/mol) through binding of the CL to the N-domain of Hsp90. Docking and undocking of the CL affects the much slower intermolecular domain movement and Hsp90's chaperone cycle governing client activation, cell viability, and stress tolerance.

| S-EPMC4273377 | biostudies-literature

Cleavage of HSP90β induced by histone deacetylase inhibitor and proteasome inhibitor modulates cell growth and apoptosis.

Project description:HSP90, one of the molecular chaperones, contributes to protein stability in most living organisms. Previously, we found cleavage of HSP90 by caspase 10 in response to treatment with histone deacetylase inhibitor or proteasome inhibitor in leukemic cell lines. In this study, we investigated this phenomenon in various cell lines and found that HSP90 was cleaved by treatment with SAHA or MG132 in 6 out of 16 solid tumor cell lines. To further investigate the effects of HSP90 cleavage on cells, we introduced mutations to the potential cleavage sites of HSP90β and found that the 294th aspartic acid residue of the protein was mainly cleaved. In the K562 and Mia-PaCa-2 cell lines expressing HSP90β D294A, the cleavage of HSP90 by the treatment with SAHA or MG132 was reduced compared with the K562 and Mia-PaCa-2 cell lines expressing HSP90β WT. Accordingly, cell growth and survival were enhanced by HSP90β D294A expression. Therefore, we suggest that HSP90 cleavage widely occurs in several cell lines, and cleavage of HSP90 may have a potential for one of the mechanisms involved in the anti-tumor effects of known drugs and novel anti-tumor drug candidates.

| S-EPMC7736425 | biostudies-literature

OPERA tau neutrino charged current interactions.

Project description:The OPERA experiment was designed to discover the vτ appearance in a vμ beam, due to neutrino oscillations. The detector, located in the underground Gran Sasso Laboratory, consisted of a nuclear photographic emulsion/lead target with a mass of about 1.25 kt, complemented by electronic detectors. It was exposed from 2008 to 2012 to the CNGS beam: an almost pure vμ beam with a baseline of 730 km, collecting a total of 1.8·1020 protons on target. The OPERA Collaboration eventually assessed the discovery of vμ→vτ oscillations with a statistical significance of 6.1 σ by observing ten vτ CC interaction candidates. These events have been published on the Open Data Portal at CERN. This paper provides a detailed description of the vτ data sample to make it usable by the whole community.

| S-EPMC8361145 | biostudies-literature

Casein Kinase 2 (CK2)-mediated Phosphorylation of Hsp90β as a Novel Mechanism of Rifampin-induced MDR1 Expression.

Project description:The P-glycoprotein (P-gp) encoded by the MDR1 gene is a drug-exporting transporter located in the cellular membrane. P-gp induction is regarded as one of the main mechanisms underlying drug-induced resistance. Although there is great interest in the regulation of P-gp expression, little is known about its underlying regulatory mechanisms. In this study, we demonstrate that casein kinase 2 (CK2)-mediated phosphorylation of heat shock protein 90β (Hsp90β) and subsequent stabilization of PXR is a key mechanism in the regulation of MDR1 expression. Furthermore, we show that CK2 is directly activated by rifampin. Upon exposure to rifampin, CK2 catalyzes the phosphorylation of Hsp90β at the Ser-225/254 residues. Phosphorylated Hsp90β then interacts with PXR, causing a subsequent increase in its stability, leading to the induction of P-gp expression. In addition, inhibition of CK2 and Hsp90β enhances the down-regulation of PXR and P-gp expression. The results of this study may facilitate the development of new strategies to prevent multidrug resistance and provide a plausible mechanism for acquired drug resistance by CK2-mediated regulation of P-gp expression.

| S-EPMC4505446 | biostudies-literature

Phosphorylation of Arabidopsis UVR8 photoreceptor modulates protein interactions and responses to UV-B radiation.

Project description:Exposure of plants to ultraviolet-B (UV-B) radiation initiates transcriptional responses that modify metabolism, physiology and development to enhance viability in sunlight. Many of these regulatory responses to UV-B radiation are mediated by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8). Following photoreception, UVR8 interacts directly with multiple proteins to regulate gene expression, but the mechanisms that control differential protein binding to initiate distinct responses are unknown. Here we show that UVR8 is phosphorylated at several sites and that UV-B stimulates phosphorylation at Serine 402. Site-directed mutagenesis to mimic Serine 402 phosphorylation promotes binding of UVR8 to REPRESSOR OF UV-B PHOTOMORPHOGENESIS (RUP) proteins, which negatively regulate UVR8 action. Complementation of the uvr8 mutant with phosphonull or phosphomimetic variants suggests that phosphorylation of Serine 402 modifies UVR8 activity and promotes flavonoid biosynthesis, a key UV-B-stimulated response that enhances plant protection and crop nutritional quality. This research provides a basis to understand how UVR8 interacts differentially with effector proteins to regulate plant responses to UV-B radiation.

| S-EPMC10858049 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data