Molecular view of ER membrane remodeling by the Sec61/TRAP translocon
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Ovis Aries (ncbitaxon:9940)
SUBMITTER: 
Ville Paavilainen
PROVIDER: MSV000090438 | MassIVE |
SECONDARY ACCESSION(S): PXD037125
REPOSITORIES: MassIVE
Similar Datasets
Project description:Protein translocation across the endoplasmic reticulum (ER) membrane is an essential step during protein entry into the secretory pathway. The conserved Sec61 protein-conducting channel facilitates polypeptide translocation and coordinates cotranslational polypeptide-processing events. In cells, the majority of Sec61 is stably associated with a heterotetrameric membrane protein complex, the translocon-associated protein complex (TRAP), yet the mechanism by which TRAP assists in polypeptide translocation remains unknown. Here, we present the structure of the core Sec61/TRAP complex bound to a mammalian ribosome by cryogenic electron microscopy (cryo-EM). Ribosome interactions anchor the Sec61/TRAP complex in a conformation that renders the ER membrane locally thinner by significantly curving its lumenal leaflet. We propose that TRAP stabilizes the ribosome exit tunnel to assist nascent polypeptide insertion through Sec61 and provides a ratcheting mechanism into the ER lumen mediated by direct polypeptide interactions.
| S-EPMC10702806 | biostudies-literature
Project description:Cross-linking MS data from the yeast Mediator complex. Cross-linking was performed using either BS3 or 1:1 mix of d0:d12 DSS. Includes unfractionated, SEC enriched, high pH reverse phase fractionated, DDA and inclusion list generated files.
2015-08-13 | MSV000079237 | MassIVE
Project description:Translational profiling methodologies enable the systematic characterization of cell types in complex tissues such as the mammalian brain, where neuronal isolation is exceptionally difficult. Here, we report a versatile strategy to profile CNS cell types in a spatiotemporally-restricted fashion by engineering a Cre-dependent adeno-associated virus expressing an EGFP-tagged ribosomal protein (AAV-FLEX-EGFPL10a) to access translating mRNAs by TRAP. We demonstrate the utility of this AAV to target a variety of genetically and anatomically defined neural populations expressing Cre recombinase and illustrate the ability of this viral TRAP (vTRAP) approach to recapitulate the molecular profiles obtained by bacTRAP in corticothalamic neurons across multiple serotypes. Furthermore, spatially restricting AAV injections enabled the elucidation of regional differences in gene expression within this cell type. Taken together, these results establish the broad applicability of the vTRAP strategy for the molecular dissection of any CNS or peripheral cell type that can be engineered to express Cre.
2017-04-10 | GSE89737 | GEO
Project description:This phase II trial is studying how well VEGF Trap works in treating patients with previously treated metastatic colorectal cancer. VEGF Trap may stop the growth of colorectal cancer by blocking blood flow to the tumor.
| 2035047 | ecrin-mdr-crc
Project description:The dynamic ribosome-translocon complex, which resides at the endoplasmic reticulum (ER) membrane, produces a major fraction of the human proteome . It governs the synthesis, translocation, membrane insertion, N-glycosylation, folding and disulfide-bond formation of nascent proteins. While individual components of this machine have been studied at high resolution in isolation, insights into their interplay in the native membrane remain limited. Here, we use electron cryo-tomography (cryo-ET), extensive classification and molecular modeling to capture molecular resolution snapshots of mRNA translation and protein maturation at the ER membrane. Comprehensively recapitulating the translational elongation cycle, we identify a highly abundant classical pre-translocation (PRE) intermediate with eEF1a in an extended conformation following the decoding state, which indicates that eEF1a remains ribosome-associated after GTP-hydrolysis during proofreading. The complete atomic structure of the most abundant ER translocon variant comprising the protein-conducting channel Sec61, the translocon-associated protein complex (TRAP) and the oligosaccharyltransferase complex A (OSTA) reveals the molecular framework for signal peptide (SP) membrane insertion and protein N-glycosylation. Associated with OSTA we observe stoichiometric and sub-stoichiometric cofactors, likely including protein isomerases. Collectively, comprehensive analysis of ER-associated protein biogenesis ex vivo reveals numerous mechanistic insights advancing beyond the study of isolated components.
2023-02-03 | PXD035475 | Pride
Project description:In fibroblasts, p65-dependent genes can be sub-divided, depending on whether they are Trap-80-dependent or -independent. To examine the generality of this grouping, we performed a microarray analysis of wild-type and Trap-80 knock-down fibroblasts, before and after stimulation of NF-kappaB activity using TNF-alpha. RNA was extracted from three independent cultures of wild-type and Trap-80 knock-down fibroblasts, before and after stimulation for 1 hour with 5ng/ml TNF-alpha. The unstimulated and stimulated wild-type samples, and the stimulated Trap-80 knock-down samples, were used for microarray analysis.
2010-04-09 | E-GEOD-12697 | biostudies-arrayexpress
Project description:While the Sec61-complex in the membrane of the human endoplasmic reticulum facilitates translocation of all precursor polypeptides with amino-terminal signal peptides or transmembrane helices, the Sec61-associated translocon-associated protein (TRAP)-complex supports translocation of only a subset of precursor polypeptides, i.e. in a substrate-specific manner. To characterize TRAP-dependent precursors, we combined siRNA-mediated TRAP depletion in HeLa cells, label-free quantitative proteomics, and differential expression analysis. Sec61 served as a positive control
2018-08-09 | PXD008178 | Pride
Project description:The translocon-associated protein (TRAP) complex resides in the endoplasmic reticulum (ER) membrane and interacts with the Sec translocon and the ribosome to facilitate biogenesis of secretory and membrane proteins. TRAP plays a key role in the secretion of many hormones, including insulin. Here we reveal the molecular architecture of the mammalian TRAP complex and how it engages the translating ribosome associated with Sec61 translocon on the ER membrane. The TRAP complex is anchored to the ribosome via a long tether and its position is further stabilized by a finger-like loop. This positions a cradle-like lumenal domain of TRAP below the translocon for interactions with translocated nascent chains. Our structure-guided TRAP mutations in Caenorhabditis elegans lead to growth deficits associated with increased ER stress and defects in protein hormone secretion. These findings elucidate the molecular basis of the TRAP complex in the biogenesis and translocation of proteins at the ER.
| S-EPMC10279528 | biostudies-literature