Oxidative Stress-dependent Perturbations of 26S Proteasome Structure
Ontology highlight
ABSTRACT: Dataset for publication submission. MS/MS and MSn analysis of in vivo cross-linked proteasomes purified from Rpn11, Rpt6, and a7-tagged 293 cell lines.
Project description:Proteasomes degrade diverse proteins in different cellular contexts through incompletely defined regulatory mechanisms. Here, we report the cryo-EM structure of thioredoxin-like protein 1 (TXNL1) bound to the 19S regulatory particle of proteasomes via interactions with PSMD1/Rpn2, PSMD4/Rpn10, and PSMD14/Rpn11. Proteasome binding is necessary for the ubiquitin-independent degradation of TXNL1 upon cellular exposure to metal- or metalloid-containing oxidative agents, thereby establishing a structural requirement for the stress-induced degradation of TXNL1.
Project description:MicroRNA regulates protein expression of cells by repressing translation of specific target messenger transcripts. Loss of the neuron specific microRNA miR-128 in Dopamine D1-receptor expressing neurons in the murine striatum (D1-MSNs) lead to increased neuronal excitability, locomotor hyperactivity and fatal epilepsy. To examine expression changes in the absence of miR-128 in D1-MSNs, we used mice expressing EGFP-tagged ribosomes in D1-MSNs with either D1-MSN-specific homozygous deletion of miR-128-2 locus or no deletion. Transcripts co-immunoprecipitated with tagged ribosomes were analyzed by microarray. 9 mutant animals ( D1-MSN-tagged ribosome; D1-MSN specific miR-128-2 homozygous deletion) and 7 age matched littermate control animals (D1-MSN-tagged ribosome only).
Project description:To realize the heterogeneity analysis of the structure and interaction for human 26S proteasomes in the cytoplasm and nucleus, combined with living cell cross-linking and efficient cytoplasm and nucleus separation method, the conformation and interaction resolution of 26S proteasome in the cytoplasm and nucleus was realized. Besides, by ensemble refinement of the interaction conformation of proteasome and ubiquitin with the crosslinking restraints, the transport path of ubiquitin on the proteasome was depicted in the cytoplasm and nucleus. It is of great significance for gaining an intensive understanding of the ubiquitin proteasome system for degrading proteins in the cytoplasm and nucleus.
Project description:Proteasomes undergo dynamic changes in their types and activities during mammalian spermatogenesis. While the spermatogenesis-specific 20S proteasome (s20S), characterized by PSMA8 substitution of PSMA7, is known to be essential for meiosis I completion, the functions of the constitutive PSMA7-containing 20S proteasomes (c20S) in spermatogenesis remain poorly understood. Here, we show that c20S proteasomes are required for the maintenance and differentiation of spermatogonia. PSMA7 is ubiquitously expressed in male germ cells beginning at the early spermatogonial stage, preceding PSMA8 expression. Conditional ablation of Psma7 using Stra8-Cre impairs proteasomal degradation in differentiating spermatogonia, leading to male infertility. Single-cell RNA sequencing analysis reveals that PSMA7-deleted germ cells are arrested at the differentiating spermatogonia stage and fail to enter meiosis. Notably, sufficient overexpression of PSMA8 restores normal spermatogenesis in Psma7-null germ cells, suggesting a potential complementarity of s20S to c20S. Therefore, our results add critical insights into the complex regulation of proteasomal degradation during spermatogenesis.
Project description:Proteasomes degrade most intracellular proteins. Several different forms of proteasomes are known. Proteasome inhibitors targeting different proteasome forms are used in clinical practice and were shown to modulate long-term potentiation (LTP) in hippocampal slices of untreated animals. Here we studied the effect of chronic administration of non-constitutive proteasome inhibitor ONX-0914 on the LTP induced by two different protocols: tetanic stimulation and theta-burst stimulation (TBS). Excitatory postsynaptic potentials (fEPSPs) in hippocampal slices from control animals and animals treated with DMSO or ONX-0914 were compared. The TBS stimulation did not change LTP kinetics in hippocampal slices, however chronic administration of ONX-0914 led to the decrease in fEPSP slopes after tetanic stimulation. Observed effects correlated with differential expression of genes involved in synaptic plasticity, glutaminergic synapse and synaptic signaling. Obtained results indicate that non-constitutive proteasomes are likely involved in the tetanus-evoked LTP but not the LTP occurring after TBS, supporting the relevance and complexity of the role of proteasomes in the synaptic plasticity.
Project description:Proximity labeling coupled to mass spectrometry enables in situ mapping of protein-protein interactions. Here, we have developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and a newly generated mouse model to monitor the interactome of proteasomes in vivo. We demonstrate that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on proteasome activity. Analysis of proteins labeled by tagged proteasomes retrieved more than half of the known proteasome-interacting proteins in a single mass spectrometry analysis, including assembly factors, activators and ubiquitin-cycle related proteins. We optimized the protocol for processing of proximity labeled samples to minimize contamination from streptavidin and implemented Data Independent Acquisition (DIA) mass spectrometry for label-free analysis. We demonstrate the utility of our workflow by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling can be used to identify both endogenous and small molecule-induced proteasome substrates.
Project description:Proximity labeling coupled to mass spectrometry enables in situ mapping of protein-protein interactions. Here, we have developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and a newly generated mouse model to monitor the interactome of proteasomes in vivo. We demonstrate that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on proteasome activity. Analysis of proteins labeled by tagged proteasomes retrieved more than half of the known proteasome-interacting proteins in a single mass spectrometry analysis, including assembly factors, activators and ubiquitin-cycle related proteins. We optimized the protocol for processing of proximity labeled samples to minimize contamination from streptavidin and implemented Data Independent Acquisition (DIA) mass spectrometry for label-free analysis. We demonstrate the utility of our workflow by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling can be used to identify both endogenous and small molecule-induced proteasome substrates.
Project description:Proximity labeling coupled to mass spectrometry enables in situ mapping of protein-protein interactions. Here, we have developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and a newly generated mouse model to monitor the interactome of proteasomes in vivo. We demonstrate that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on proteasome activity. Analysis of proteins labeled by tagged proteasomes retrieved more than half of the known proteasome-interacting proteins in a single mass spectrometry analysis, including assembly factors, activators and ubiquitin-cycle related proteins. We optimized the protocol for processing of proximity labeled samples to minimize contamination from streptavidin and implemented Data Independent Acquisition (DIA) mass spectrometry for label-free analysis. We demonstrate the utility of our workflow by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling can be used to identify both endogenous and small molecule-induced proteasome substrates.
Project description:Proximity labeling coupled to mass spectrometry enables in situ mapping of protein-protein interactions. Here, we have developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and a newly generated mouse model to monitor the interactome of proteasomes in vivo. We demonstrate that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on proteasome activity. Analysis of proteins labeled by tagged proteasomes retrieved more than half of the known proteasome-interacting proteins in a single mass spectrometry analysis, including assembly factors, activators and ubiquitin-cycle related proteins. We optimized the protocol for processing of proximity labeled samples to minimize contamination from streptavidin and implemented Data Independent Acquisition (DIA) mass spectrometry for label-free analysis. We demonstrate the utility of our workflow by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling can be used to identify both endogenous and small molecule-induced proteasome substrates.
Project description:Proximity labeling coupled to mass spectrometry enables in situ mapping of protein-protein interactions. Here, we have developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and a newly generated mouse model to monitor the interactome of proteasomes in vivo. We demonstrate that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on proteasome activity. Analysis of proteins labeled by tagged proteasomes retrieved more than half of the known proteasome-interacting proteins in a single mass spectrometry analysis, including assembly factors, activators and ubiquitin-cycle related proteins. We optimized the protocol for processing of proximity labeled samples to minimize contamination from streptavidin and implemented Data Independent Acquisition (DIA) mass spectrometry for label-free analysis. We demonstrate the utility of our workflow by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling can be used to identify both endogenous and small molecule-induced proteasome substrates.