Comparative analysis of gene expression between overexpression and deficiency of signal peptide peptidase in Arabidopsis thaliana
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PROVIDER: PRJNA530177 | ENA |
REPOSITORIES: ENA
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Project description:Signal peptide peptidase (SPP) plays an essential role in among all eukaryotes. The knock out lines of A. thaliana SPP (AtSPP) is lethal and the substrates of AtSPP are not identified. Based on the situation, we constructed the plants with AtSPP over-expressed and knock down to investigate the role of AtSPP. We also used the data to find the candidate substrates of AtSPP, which regulates intermembrane proteolysis, would have crucial physiological functions as well as control the gene expression encoding the substrates.
2019-09-01 | GSE129113 | GEO
Project description:The ER-resident signal peptidase complex (SPC) is an essential membrane protein complex involved in the maturation of soluble and type-I transmembrane proteins destined to the secretory pathway. As a part of the ER translocon machinery, the SPC removes signal peptides (SPs) from the N-termini of many proteins such as hormones, antibodies, or secretory enzymes1,2. To accomplish this task, the SPC must process a large variety of SPs with an exquisite specificity. Although the determinants of SP recognition have been established empirically3, the molecular details of SP recognition and removal remain elusive. Here, we show that the human SPC exists in two functional paralogs with distinct proteolytic subunits. We determined the structures and posttranslational modifications of both paralogs using electron cryo-microscopy and structural proteomics. The respective proteolytic subunits SEC11A and SEC11C adopt a conserved signal peptidase (SPase) fold with their active sites facing a prominent transmembrane window, which is collectively formed by the transmembrane domains of all SPC subunits. Characteristic, charged regions on both sides of this window locally thin the membrane by approximately 40% compared to the exterior. The data suggest a mechanistic model for SPC specificity and the transfer of SPs from the Sec61 translocation channel to the SPC.
2021-07-05 | PXD022002 | Pride
Project description:iRhoms are pseudoprotease members of the rhomboid-like superfamily and are cardinal regulators of inflammatory and growth factor signaling; they function primarily by recognizing transmembrane domains of their clients. Here, we report a mechanistically distinct nuclear function of iRhoms, showing that both human and mouse iRhom2 are non-canonical substrates of signal peptidase complex (SPC), the protease that removes signal peptides from secreted proteins. Cleavage of iRhom2 generates an N-terminal fragment that enters the nucleus and modifies the transcriptome, in part by binding C-terminal binding proteins (CtBPs). The biological significance of nuclear iRhom2 is indicated by elevated levels in skin biopsies of patients with psoriasis, tylosis with oesophageal cancer (TOC), and non-epidermolytic palmoplantar keratoderma (NEPPK); increased iRhom2 cleavage in a keratinocyte model of psoriasis; and nuclear iRhom2 promoting proliferation of keratinocytes. Overall, this work identifies an unexpected SPC-dependent ER-to-nucleus signaling pathway and demonstrates that iRhoms can mediate nuclear signaling.
2024-01-04 | GSE219008 | GEO
Project description:The M genome segment of Bunyamwera virus (BUNV)-the prototype of both the Bunyaviridae family and the Orthobunyavirus genus-encodes the glycoprotein precursor (GPC) that is proteolytically cleaved to yield two viral structural glycoproteins, Gn and Gc, and a nonstructural protein, NSm. The cleavage mechanism of orthobunyavirus GPCs and the host proteases involved have not been clarified. In this study, we investigated the processing of BUNV GPC and found that both NSm and Gc proteins were cleaved at their own internal signal peptides (SPs), in which NSm domain I functions as SP(NSm) and NSm domain V as SP(Gc) Moreover, the domain I was further processed by a host intramembrane-cleaving protease, signal peptide peptidase, and is required for cell fusion activities. Meanwhile, the NSm domain V (SP(Gc)) remains integral to NSm, rendering the NSm topology as a two-membrane-spanning integral membrane protein. We defined the cleavage sites and boundaries between the processed proteins as follows: Gn, from residue 17-312 or nearby residues; NSm, 332-477; and Gc, 478-1433. Our data clarified the mechanism of the precursor cleavage process, which is important for our understanding of viral glycoprotein biogenesis in the genus Orthobunyavirus and thus presents a useful target for intervention strategies.
| S-EPMC4978261 | biostudies-literature
Project description:Effect of expression of dipeptidyl peptidase-IV (DPP-IV) in U373 cell line on uncontrolled cell proliferation and aberrant interactions with the brain extracellular matrix.
2011-12-31 | E-MTAB-583 | biostudies-arrayexpress
Project description:Signal peptide peptidase (SPP), a member of the presenilin-like intra-membrane cleaving aspartyl protease family, migrates on Blue Native (BN) gels as 100 kDa, 200 kDa and 450 kDa species. SPP has recently been implicated in other non-proteolytic functions such as retro-translocation of MHC Class I molecules and binding of misfolded proteins in the endoplasmic reticulum (ER). These high molecular weight SPP complexes might contain additional proteins that regulate the proteolytic activity of SPP or support its non-catalytic functions.In this study, an unbiased iTRAQ-labeling mass spectrometry approach was used to identify SPP-interacting proteins. We found that vigilin, a ubiquitous multi-KH domain containing cytoplasmic protein involved in RNA binding and protein translation control, selectively enriched with SPP. Vigilin interacted with SPP and both proteins co-localized in restricted intracellular domains near the ER, biochemically co-fractionated and were part of the same 450 kDa complex on BN gels. However, vigilin does not alter the protease activity of SPP, suggesting that the SPP-vigilin interaction might be involved in the non-proteolytic functions of SPP.We have identified and validated vigilin as a novel interacting partner of SPP that could play an important role in the non-proteolytic functions of SPP. This data adds further weight to the idea that intramembrane-cleaving aspartyl proteases, such as presenilin and SPPs, could have other functions besides the proteolysis of short membrane stubs.
| S-EPMC3490818 | biostudies-other
Project description:Signal peptide peptidase (SPP) is an atypical aspartic protease that hydrolyzes peptide bonds within the transmembrane domain of substrates and is implicated in several biological and pathological functions. Here, we analyzed the structure of human SPP by electron microscopy and reconstructed the three-dimensional structure at a resolution of 22 Å. Enzymatically active SPP forms a slender, bullet-shaped homotetramer with dimensions of 85 × 85 × 130 Å. The SPP complex has four concaves on the rhombus-like sides, connected to a large chamber inside the molecule. Intriguingly, the N-terminal region of SPP is sufficient for the tetrameric assembly. Moreover, overexpression of the N-terminal region inhibited the formation of the endogenous SPP tetramer and the proteolytic activity within cells. These data suggest that the homotetramer is the functional unit of SPP and that its N-terminal region, which works as the structural scaffold, has a novel modulatory function for the intramembrane-cleaving activity of SPP.
| S-EPMC3138278 | biostudies-literature
Project description:Veterinary trypanocidal benzoxaboroles are peptidase-activated prodrugs
| PRJEB34627 | ENA
Project description:BACKGROUND: Type I signal peptidases (SPases) are essential membrane-bound serine proteases responsible for the cleavage of signal peptides from proteins that are translocated across biological membranes. The crystal structure of SPase in complex with signal peptide has not been solved and their substrate-binding site and binding specificities remain poorly understood. We report here a structure-based model for Escherichia coli DsbA 13-25 in complex with its endogenous type I SPase. RESULTS: The bound structure of DsbA 13-25 in complex with its endogenous type I SPase reported here reveals the existence of an extended conformation of the precursor protein with a pronounced backbone twist between positions P3 and P1'. Residues 13-25 of DsbA occupy, and thereby define 13 subsites, S7 to S6', within the SPase substrate-binding site. The newly defined subsites, S1' to S6' play critical roles in the substrate specificities of E. coli SPase. Our results are in accord with available experimental data. CONCLUSION: Collectively, the results of this study provide interesting new insights into the binding conformation of signal peptides and the substrate-binding site of E. coli SPase. This is the first report on the modeling of a precursor protein into the entire SPase binding site. Together with the conserved precursor protein binding conformation, the existing and newly identified substrate binding sites readily explain SPase cleavage fidelity, consistent with existing biochemical results and solution structures of inhibitors in complex with E. coli SPase. Our data suggests that both signal and mature moiety sequences play important roles and should be considered in the development of predictive tools.
| S-EPMC2259416 | biostudies-literature
Project description:We identified the Drosophila melanogaster Signal peptide peptidase gene (Spp) that encodes a multipass transmembrane aspartyl protease. Drosophila SPP is homologous to the human signal peptide peptidase (SPP) and is distantly related to the presenilins. We show that, like human SPP, Drosophila SPP can proteolyze a model signal peptide and is sensitive to an SPP protease inhibitor and that it localizes to the endoplasmic reticulum. Expression of Drosophila SPP was first apparent at germ band extension, and in late embryos it was robust in the salivary glands, proventriculus, and tracheae. Flies bearing mutations in conserved residues or carrying deficiencies for the Spp gene had defective tracheae and died as larvae.
| S-EPMC1449732 | biostudies-literature