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Hessa, Tara
Publications (10 of 10) Show all publications
Talamonti, E., Sasso, V., To, H., Haslam, R. P., Napier, J. A., Ulfhake, B., . . . Viscomi, M. T. (2020). Impairment of DHA synthesis alters the expression of neuronal plasticity markers and the brain inflammatory status in mice. The FASEB Journal, 34(2), 2024-2040
Open this publication in new window or tab >>Impairment of DHA synthesis alters the expression of neuronal plasticity markers and the brain inflammatory status in mice
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2020 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 34, no 2, p. 2024-2040Article in journal (Refereed) Published
Abstract [en]

Docosahexaenoic acid (DHA) is a omega-3 fatty acid typically obtained from the diet or endogenously synthesized through the action of elongases (ELOVLs) and desaturases. DHA is a key central nervous system constituent and the precursor of several molecules that regulate the resolution of inflammation. In the present study, we questioned whether the impaired synthesis of DHA affected neural plasticity and inflammatory status in the adult brain. To address this question, we investigated neural and inflammatory markers from mice deficient for ELOVL2 (Elovl2(-/-)), the key enzyme in DHA synthesis. From our findings, Elovl2(-/-) mice showed an altered expression of markers involved in synaptic plasticity, learning, and memory formation such as Egr-1, Arc1, and BDNF specifically in the cerebral cortex, impacting behavioral functions only marginally. In parallel, we also found that DHA-deficient mice were characterized by an increased expression of pro-inflammatory molecules, namely TNF, IL-1 beta, iNOS, caspase-1 as well as the activation and morphologic changes of microglia in the absence of any brain injury or disease. Reintroducing DHA in the diet of Elovl2(-/-) mice reversed such alterations in brain plasticity and inflammation. Hence, impairment of systemic DHA synthesis can modify the brain inflammatory and neural plasticity status, supporting the view that DHA is an essential fatty acid with an important role in keeping inflammation within its physiologic boundary and in shaping neuronal functions in the central nervous system.

Keywords
anti-inflammatory molecules, brain plasticity, microglia, omega-3, PUFA
National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-180460 (URN)10.1096/fj.201901890RR (DOI)000514663600009 ()31909582 (PubMedID)
Available from: 2020-04-14 Created: 2020-04-14 Last updated: 2022-03-23Bibliographically approved
Andersson, A., Kudva, R., Magoulopoulou, A., Lejarre, Q., Lara, P., Xu, P., . . . Tellgren-Roth, Å. (2020). Membrane integration and topology of RIFIN and STEVOR proteins of the Plasmodium falciparum parasite. The FEBS Journal, 287(13), 2744-2762
Open this publication in new window or tab >>Membrane integration and topology of RIFIN and STEVOR proteins of the Plasmodium falciparum parasite
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2020 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 287, no 13, p. 2744-2762Article in journal (Refereed) Published
Abstract [en]

The malarial parasite Plasmodium exports its own proteins to the cell surfaces of red blood cells (RBCs) during infection. Examples of exported proteins include members of the repetitive interspersed family (RIFIN) and subtelomeric variable open reading frame (STEVOR) family of proteins from Plasmodium falciparum. The presence of these parasite-derived proteins on surfaces of infected RBCs triggers the adhesion of infected cells to uninfected cells (rosetting) and to the vascular endothelium potentially obstructing blood flow. While there is a fair amount of information on the localization of these proteins on the cell surfaces of RBCs, less is known about how they can be exported to the membrane and the topologies they can adopt during the process. The first step of export is plausibly the cotranslational insertion of proteins into the endoplasmic reticulum (ER) of the parasite, and here, we investigate the insertion of three RIFIN and two STEVOR proteins into the ER membrane. We employ a well-established experimental system that uses N-linked glycosylation of sites within the protein as a measure to assess the extent of membrane insertion and the topology it assumes when inserted into the ER membrane. Our results indicate that for all the proteins tested, transmembranes (TMs) 1 and 3 integrate into the membrane, so that the protein assumes an overall topology of Ncyt-Ccyt. We also show that the segment predicted to be TM2 for each of the proteins likely does not reside in the membrane, but is translocated to the lumen.

Keywords
membrane protein topology, N-linked glycosylation, Plasmodium, RIFIN protein, STEVOR protein
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-177797 (URN)10.1111/febs.15171 (DOI)000504344200001 ()31821735 (PubMedID)
Available from: 2020-01-21 Created: 2020-01-21 Last updated: 2022-02-26Bibliographically approved
Kriegler, T., Lang, S., Notari, L. & Hessa, T. (2020). Prion Protein Translocation Mechanism Revealed by Pulling Force Studies. Journal of Molecular Biology, 432(16), 4447-4465
Open this publication in new window or tab >>Prion Protein Translocation Mechanism Revealed by Pulling Force Studies
2020 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 432, no 16, p. 4447-4465Article in journal (Refereed) Published
Abstract [en]

The mammalian prion protein (PrP) engages with the ribosome-Sec61 translocation channel complex to generate different topological variants that are either physiological, or involved in neurodegenerative diseases. Here, we describe cotranslational folding and translocation mechanisms of PrP coupled to an Xbp1-based arrest peptide (AP) as folding sensor, to measure forces acting on PrP nascent chain. Our data reveal two main pulling events followed by a minor third one exerted on the nascent chains during their translocation. Using those force landscapes, we show that a specific sequence within an intrinsically disordered region, containing a polybasic and glycine-proline rich residues, modulates the second pulling event by interacting with TRAP complex. This work also delineates the sequence of events involved in generation of PrP toxic transmembrane topologies during its synthesis. Our results shed new insight into the folding of such a topological complex protein, where marginal pulling by the signal sequence, together with the flanking downstream sequence in the mature domain, primarily drives an overall inefficient translocation resulting in the nascent chain to adopt alternative topologies.

Keywords
prion protein, co-translation folding, arrest peptide, Xbp1, ER translocation
National Category
Biochemistry and Molecular Biology
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-183405 (URN)10.1016/j.jmb.2020.05.022 (DOI)000552832700009 ()32502491 (PubMedID)
Available from: 2020-07-08 Created: 2020-07-08 Last updated: 2022-02-26Bibliographically approved
Kriegler, T., Lang, S., Notari, L. & Hessa, T. (2020). Supporting data on prion protein translocation mechanism revealed by pulling force studies. Data in Brief, 31, Article ID 105931.
Open this publication in new window or tab >>Supporting data on prion protein translocation mechanism revealed by pulling force studies
2020 (English)In: Data in Brief, E-ISSN 2352-3409, Vol. 31, article id 105931Article in journal (Refereed) Published
Abstract [en]

The Prion protein (PrP) is a highly conserved cell surface glycoprotein. To enter the secretory pathway, the PrP precursor relies on the Sec61 complex and multiple accessory factors all gathering at the membrane of the Endoplasmic reticulum (ER). PrP topogenesis results in the formation of different PrP isoforms. Aside from the typical secretory variant (SecPrP) different pathognomonic, membrane-embedded variants (NtmPrP and CtmPrP) that are associated with neurodegenerative diseases can be found [1]. In this article, we provide supportive data related to “Prion Protein Translocation Mechanism Revealed by Pulling Force Studies” (Kriegler et al., May 2020)[2], where we utilize Xbp1 arrest peptide (AP)-mediated ribosomal stalling to study the co-translational folding experienced by PrP during its insertion into the ER. We measure translocation efficiency and characterize the force exerted on PrP nascent chain so called “pulling force profile”. Here, we describe the method of AP-mediated ribosomal stalling assay together with additional experimental data to the main article. Furthermore, we describe the combination of AP-mediated ribosomal stalling and semi-permeabilized Hela cells (SPCs) as ER membrane source. Using this experimental set-up one can directly determine the contribution of a specific membrane component, e.g. subunits of the ER protein translocase, as pulling factor exerting force on the PrP nascent chain.

The data presented here covers (a) the SDS-PAGE gel images visualized by autoradiography, (b) quantification of the different populations of PrP species observed in the AP-mediated ribosomal stalling method, and (c) calculation formulas of the pulling force profiles measured in SPCs in comparison to dog pancreas microsomes as ER membrane donor. Finally, Western Blot analysis and quantification of siRNA knockdown levels compared to control conditions of various translocation components are shown.

Keywords
Prion protein, XBP1-arrest peptide, Cotranslational folding, Pulling forcesemi-permeabilized cells
National Category
Biochemistry and Molecular Biology
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-183407 (URN)10.1016/j.dib.2020.105931 (DOI)000569214200030 ()
Available from: 2020-07-07 Created: 2020-07-07 Last updated: 2022-02-26Bibliographically approved
Kriegler, T., Kiburg, G. & Hessa, T. (2020). Translocon-Associated Protein Complex (TRAP) is Crucial for Co-Translational Translocation of Pre-Proinsulin. Journal of Molecular Biology, 432(24), Article ID 166694.
Open this publication in new window or tab >>Translocon-Associated Protein Complex (TRAP) is Crucial for Co-Translational Translocation of Pre-Proinsulin
2020 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 432, no 24, article id 166694Article in journal (Refereed) Published
Abstract [en]

Many unanswered questions remain in understanding the biosynthesis of the peptide hormone insulin. Here we elucidate new aspects in the mechanism of co-translational translocation initiation of pre-proinsulin in the endoplasmic reticulum. We utilize a translational arrest peptide derived from the x-boxbinding protein (Xbp1) to induce ribosomal stalling and generate translocation intermediates. We find that the insulin signal sequence is rather weakly gating and requires the assistance of auxiliary translocon components to initiate translocation. Probing the translational intermediates with chemical crosslinking, we identified an early interaction with the translocon-associated protein (TRAP) complex. The TRAP beta subunit interacts with pre-proinsulin before the peptide enters the Sec61 translocon channel in a signal sequence-dependent manner. We describe the substrate sequence determinants that are recognized by TRAP on the cytosolic site of the membrane to facilitate substrate-specific opening of the Sec61 translocon channel. Our findings support the hypothesis that the TRAP-dependence is in part determined by the content of glycine and proline residues mainly within the signal sequence.

Keywords
pre-proinsulin, TRAP complex, co-translation folding, Xbp1, ER translocation
National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-189922 (URN)10.1016/j.jmb.2020.10.028 (DOI)000599752700007 ()33137310 (PubMedID)
Available from: 2021-02-26 Created: 2021-02-26 Last updated: 2022-02-25Bibliographically approved
Kriegler, T., Magoulopoulou, A., Marchal, R. A. & Hessa, T. (2018). Measuring Endoplasmic Reticulum Signal Sequences Translocation Efficiency Using the Xbp1 Arrest Peptide. Cell Chemical Biology, 25(7), 880-890
Open this publication in new window or tab >>Measuring Endoplasmic Reticulum Signal Sequences Translocation Efficiency Using the Xbp1 Arrest Peptide
2018 (English)In: Cell Chemical Biology, ISSN 2451-9456, E-ISSN 2451-9448, Vol. 25, no 7, p. 880-890Article in journal (Refereed) Published
Abstract [en]

Secretory proteins translocate across the mammalian ER membrane co-translationally via the ribosome-sec61 translocation machinery. Signal sequences within the polypeptide, which guide this event, are diverse in their hydrophobicity, charge, length, and amino acid composition. Despite the known sequence diversity in the ER signals, it is generally assumed that they have a dominant role in determining co-translational targeting and translocation process. We have analyzed co-translational events experienced by secretory proteins carrying efficient versus inefficient signal sequencing, using an assay based on Xbp1 peptide-mediated translational arrest. With this method we were able to measure the functional efficiency of ER signal sequences. We show that an efficient signal sequence experiences a two-phase event whereby the nascent chain is pulled from the ribosome during its translocation, thus resuming translation and yielding full-length products. Conversely, the inefficient signal sequence experiences a single weaker pulling event, suggesting inadequate engagement by the translocation machinery of these marginally hydrophobic signal sequences.

National Category
Biological Sciences
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-159061 (URN)10.1016/j.chembiol.2018.04.006 (DOI)000439177400010 ()29754956 (PubMedID)
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2022-02-26Bibliographically approved
Nilsson, I., Lara, P., Hessa, T., Johnson, A. E., von Heijne, G. & Karamyshev, A. L. (2015). The Code for Directing Proteins for Trans location across ER Membrane: SRP Cotranslationally Recognizes Specific Features of a Signal Sequence. Journal of Molecular Biology, 427(6), 1191-1201
Open this publication in new window or tab >>The Code for Directing Proteins for Trans location across ER Membrane: SRP Cotranslationally Recognizes Specific Features of a Signal Sequence
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2015 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 427, no 6, p. 1191-1201Article in journal (Refereed) Published
Abstract [en]

The signal recognition particle (SRP) cotranslationally recognizes signal sequences of secretory proteins and targets ribosome-nascent chain complexes to the SRP receptor in the endoplasmic reticulum membrane, initiating translocation of the nascent chain through the Sec61 translocon. Although signal sequences do not have homology, they have similar structural regions: a positively charged N-terminus, a hydrophobic core and a more polar C-terminal region that contains the cleavage site for the signal peptidase. Here, we have used site-specific photocrosslinking to study SRP signal sequence interactions. A photoreactive probe was incorporated into the middle of wild-type or mutated signal sequences of the secretory protein preprolactin by in vitro translation of mRNAs containing an amber-stop codon in the signal peptide in the presence of the N-epsilon-(5-azido-2 nitrobenzoyl)-Lys-tRNA(amb) amber suppressor. A homogeneous population of SRP ribosome-nascent chain complexes was obtained by the use of truncated mRNAs in translations performed in the presence of purified canine SRP. Quantitative analysis of the photoadducts revealed that charged residues at the N-terminus of the signal sequence or in the early part of the mature protein have only a mild effect on the SRP signal sequence association. However, deletions of amino acid residues in the hydrophobic portion of the signal sequence severely affect SRP binding. The photocrosslinking data correlate with targeting efficiency and translocation across the membrane. Thus, the hydrophobic core of the signal sequence is primarily responsible for its recognition and binding by SRP, while positive charges fine-tune the SRP signal sequence affinity and targeting to the translocon.

National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-116784 (URN)10.1016/j.jmb.2014.06.014 (DOI)000351798500005 ()24979680 (PubMedID)
Note

AuthorCount:6;

Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2022-02-23Bibliographically approved
Hessa, T., Meindl-Beinker, N. M., Bernsel, A., Kim, H., Sato, Y., Lerch-Bader, M., . . . von Heijne, G. (2007). Molecular code for transmembrane-helix recognition by the Sec61 translocon. Nature, 450(7172), 1026-1030
Open this publication in new window or tab >>Molecular code for transmembrane-helix recognition by the Sec61 translocon
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2007 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 450, no 7172, p. 1026-1030Article in journal (Refereed) Published
Abstract [en]

Transmembrane alpha-helices in integral membrane proteins are recognized co-translationally and inserted into the membrane of the endoplasmic reticulum by the Sec61 translocon. A full quantitative description of this phenomenon, linking amino acid sequence to membrane insertion efficiency, is still lacking. Here, using in vitro translation of a model protein in the presence of dog pancreas rough microsomes to analyse a large number of systematically designed hydrophobic segments, we present a quantitative analysis of the position- dependent contribution of all 20 amino acids to membrane insertion efficiency, as well as of the effects of transmembrane segment length and flanking amino acids. The emerging picture of translocon- mediated transmembrane helix assembly is simple, with the critical sequence characteristics mirroring the physical properties of the lipid bilayer.

National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-25367 (URN)10.1038/nature06387 (DOI)000251579900075 ()
Available from: 2008-08-28 Created: 2008-08-28 Last updated: 2022-02-25Bibliographically approved
Hessa, T., Kim, H., Bihlmaier, K., Lundin, C., Boekel, J., Andersson, H., . . . von Heijne, G. (2005). Recognition of transmembrane helices by the endoplasmic reticulum translocon. Nature, 433(7024), 377-381
Open this publication in new window or tab >>Recognition of transmembrane helices by the endoplasmic reticulum translocon
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2005 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 433, no 7024, p. 377-381Article in journal (Refereed) Published
Abstract [en]

Membrane proteins depend on complex translocation machineries for insertion into target membranes. Although it has long been known that an abundance of nonpolar residues in transmembrane helices is the principal criterion for membrane insertion, the specific sequence-coding for transmembrane helices has not been identified. By challenging the endoplasmic reticulum Sec61 translocon with an extensive set of designed polypeptide segments, we have determined the basic features of this code, including a 'biological' hydrophobicity scale. We find that membrane insertion depends strongly on the position of polar residues within transmembrane segments, adding a new dimension to the problem of predicting transmembrane helices from amino acid sequences. Our results indicate that direct protein - lipid interactions are critical during translocon-mediated membrane insertion.

National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-22860 (URN)10.1038/nature03216 (DOI)000226546200033 ()
Available from: 2006-08-30 Created: 2006-08-30 Last updated: 2022-02-25Bibliographically approved
Hessa, T., Bernsel, A., Sato, Y., Lerch Bader, M., Nilsson, I., White, S. & von Heijne, G.A quantitative analysis of translocon-mediated insertion of transmembrane alpha-helices.
Open this publication in new window or tab >>A quantitative analysis of translocon-mediated insertion of transmembrane alpha-helices
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(English)Manuscript (Other academic)
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-22862 (URN)
Available from: 2006-08-30 Created: 2006-08-30 Last updated: 2022-02-25Bibliographically approved
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