Publications

38. Cavini IA, Fontes MG, Zeraik AE, Lopes JL, Araujo APU. Novel lipid-interaction motifs within the C-terminal domain of Septin10 from Schistosoma mansoni. (BBA)-Biomembranes, 2024; 1866(7), 184371. doi.org/10.1016/j.bbamem.2024.184371

We show that SmSEPT10 CTD contains a conserved polybasic region (PB3), which is present in both animals and fungi septins, and a Lys (K367) within its putative amphipathic helix (AH) that we demonstrate as important for lipid binding.

37. Mendonça DC, Morais STB, Ciol H, Pinto APA, Leonardo DA, Pereira HM, Valadares NF, Portugal RV, Klaholz BP, Araujo APU. Structural Insights into Ciona intestinalis Septins: Complexes Suggest a Mechanism for Nucleotide-dependent Interfacial Cross-talk. J. Mol. Biol., 2024;168693. doi.org/10.1016/j.jmb.2024.168693

Here, we show that C. intestinalis septins present a similar biochemistry to their human orthologues and also provide the cryo-EM structures of an octamer, a hexamer and a tetrameric sub-complex.

36. Cavini IA, Winter AJ, D’Muniz Pereira H, Woolfson DN, Crump MP, Garratt RC. X-ray structure of the metastable SEPT14-SEPT7 coiled coil reveals a hendecad region crucial for heterodimerization. Acta Crystallogr. D, 2023; D79, 881-894. doi.org/10.1107/S2059798323006514

Report of the first structure of a septin hetero coiled coil. The X-ray structure of the SEPT14-SEPT7 coiled coil presents several packing imperfections, generating a hotspot for interaction with partners. We also present SEC-SAXS data corroborating the parallel orientation of the coiled coil (and of other human homologs) in solution.

35. Silva RM, Saladino GCR, Leonardo DA, Pereira HM, Sculaccio SA, Araujo APU, Garratt RC. A Key Piece of the Puzzle: The central tetramer of the Saccharomyces cerevisiae septin protofilament and Its Implications for Self-Assembly. J. Struct. Biol. 2023;107983. doi.org/10.1016/j.jsb.2023.107983

Here we present crystal structures of Cdc3/Cdc10. Switch I from Cdc10 contributes significantly to the interface, whereas in Cdc3 it is largely disorded. At the NC-interface, we describe an elegant means by which the sidechain of a glutamine from helix α0 imitates a peptide group at the kink between helices α5 and α6 in the neighbouring subunit.

34. Castro DKSV, Rosa HVD, Mendonça DC, Cavini IA, Araujo APU, Garratt RC. Dissecting the binding interface of the septin polymerization enhancer Borg BD3. J Mol Biol. 2023;168132. doi.org/10.1016/j.jmb.2023.168132

Aided by an AF model, we have dissected the binding interface of Borg’s BD3 motif to the heterodimeric septin coiled coil SEPT6-SEPT7. It interacts with the furrow formed by the helices of the parallel CC. Upon binding in vitro, it leads to an exacerbated septin polymerization. The manuscript also contains polymerization studies on CTD-truncated septin complexes.

33. Fernandes AF, Leonardo DA, Cavini IA, Rosa HVD, Vargas JA, Pereira HM, Nascimento AS, Garratt RC. Conservation and divergence of the G-interfaces of Drosophila melanogaster septins. Cytoskeleton. 2022. Online ahead of print. doi.org/10.1002/cm.21740

First report on D. melanogaster septin structure. The G-domain heterodimeric structure of Sep1 and Sep2 was solved, bearing significant resemblance to its human counterparts; In Pnut, a square residue interaction present in the homodimeric G-interface of human SEPT7 is absent.

32. Cavini IA,  Leonardo DA, Rosa HVD, Castro DKSV, Valadares NF, Pereira HM, Araujo APU,  Garratt RC. The structural biology of septins and their filaments: an update. Front Cell Dev Biol. 2021;9:3246. doi.org/10.3389/fcell.2021.765085

This review is an update on the structural biology of septins. New information has been unraveled since the publication of the last review (Valadares et al. 2017), including the reordering of the human core particle, the specificities found on G-interfaces, the release of alpha-0 helix to likely interact with membranes, the antiparallel coiled coils formed by the C-terminal domains, the cavity present in the cryo-EM SEPT2/6/7 structure and the flexibility modes core particles have.

31. Mendonça DC, Guimarães SL,  Pereira HM, Pinto AA, de Farias MA, de Godoy AS, Araujo APU,  Heel M, Portugal RV, Garratt RC. An atomic model for the human septin hexamer by cryo-EM. J Mol Biol. 2021;433:167096. doi.org/10.1016/j.jmb.2021.167096 

Cryo-EM structure of SEPT2-6-7-7-6-2 hexamer at 3.6 Å resolution. We describe a cavity at the so-called NC-interface which is probably related to the storage of a basic α-helix whose release may provide a mechanism for controlling membrane association. Local flexibility shows that the particle tends to bend at its centre which appears related to the way filaments recognize the curvature of biological membranes for which there is growing evidence.

30.  Leonardo DA, Cavini IA, Sala FA, Mendonça DC, Rosa HVD, Kumagai PS, Crusca Jr E, Valadares NF, Marques IA, Brandão-Neto J, Munte CE, Kalbitzer HR, Soler N, Usón I, André I, Araujo APU, Pereira HM, Garratt RC. Orientational ambiguity in septin coiled coils and its structural basis. J Mol Biol. 2021;433:166889. doi.org/10.1016/j.jmb.2021.166889

We have determined the structures of the coiled-coil regions for five human septins (SEPT1, SEPT4, SEPT5, SEPT6 and SEPT8) and show that these can adopt both parallel and antiparallel orientations. In the case of the antiparallel coiled coils, a completely novel interface is observed which is characterized by hydrophilic residues in the a position leading to a continuous chain of interactions (hydrogen bonds and salt bridges).

29. Zeraik AE, Fontes MG, DeMarco R. Biophysical Analysis of Schistosoma mansoni Septins. In: Schistosoma mansoni. Springer; 2020. p. 197–210. doi.org/10.1007/978-1-0716-0635-3_16

28. Castro DKSV, da Silva SM de O, Pereira HM, Macedo JNA, Leonardo DA, Valadares NF, Kumagai PS, Brandão-Neto J, Araújo APU, Garratt RC. A complete compendium of crystal structures for the human SEPT3 subgroup reveals functional plasticity at a specific septin interface. IUCrJ. 2020;7. doi.org/10.1107/S2052252520002973

An essential complete set of SEPT3-group structures, with seven structures (SEPT3, SEPT9 and SEPT12) bound to GDP and GTP-analogues and showing different NC-interfaces (open, closed and shifted). We propose the squeezing mechanism of the NC-interface, releasing the α0 helix which contains a polybasic region (PB1) to probably interact with membranes.

27. Rosa HVD, Leonardo DA, Brognara G, Brandão-Neto J, Pereira HM, Araújo APU, Garratt RC. Molecular recognition at septin interfaces: the switches hold the key. J Mol Biol. 2020;432:5784–801. doi.org/10.1016/j.jmb.2020.09.001

We have determined the only high-resolution crystal structures of dimeric heterocomplexes of human septins (SEPT2-SEPT6, SEPT2-SEPT8, SEPT2-SEPT11 and SEPT7-SEPT3_T282Y) providing for the first time a detailed view of the interface and a better understanding of the basis of complex specificity. Furthermore, this has led us to speculate that SEPT2 may form a non-conventional covalent bond with SEPT6 (or SEPT11) involving a cysteine and a lysine residues.

26. Kumagai PS, Martins CS, Sales EM, Rosa HVD, Mendonça DC, Damalio JCP, Spinozzi F, Itri R, Araújo APU. Correct partner makes the difference: Septin G-interface plays a critical role in amyloid formation. Int J Biol Macromol. 2019;133:428–35. doi.org/10.1016/j.ijbiomac.2019.04.105

25. Zuvanov L, Mota DMD, Araujo APU, DeMarco R. A blueprint of septin expression in human tissues. Funct Integr Genomics. 2019;19:787–97. doi.org/10.1007/s10142-019-00690-3

24. Omrane M, Camara AS, Taveneau C, Benzoubir N, Tubiana T, Yu J, Guérois R, Samuel D, Goud B, Poüs C, Bressanelli S, Garratt RC, Thiam AR, Gassama-Diagne A. Septin 9 has two polybasic domains critical to septin filament assembly and golgi integrity. iScience. 2019;13:138–53. doi.org/10.1016/j.isci.2019.02.015

23. Mendonça DC, Macedo JN, Guimarães SL, da Silva FLB, Cassago A, Garratt RC, Portugal RV, Araújo APU. A revised order of subunits in mammalian septin complexes. Cytoskeleton. 2019;76:457–66. doi.org/10.1002/cm.21569

Correcting the order of septins within the hexameric core particle. Before this, it has been systematically reported in the literature that the hexamer is built as follows: 7-6-2-2-6-7. However, using negative stain TEM we conclusively show that, in fact, the correct order is 2-6-7-7-6-2. This may have significant consequences for how filaments assemble. Elected 2019 Cytoskeleton Paper of the Year.

22. Brognara G, Pereira HD, Brandão-Neto J, Araujo APU, Garratt RC. Revisiting SEPT7 and the slippage of β-strands in the septin family. J Struct Biol. 2019;207:67–73. doi.org/10.1016/j.jsb.2019.04.015

We have recently rationalized the phenomenon of β-strand slippage in septins which has remained rather enigmatic ever since our original description of the phenomenon. This was possible due to solving two new structures for SEPT7 complexed to GDP, one in the presence of Mg2+ and the other in its absence.

21. Pinto APA, Pereira HM, Zeraik AE, Ciol H, Ferreira FM, Brandão-Neto J, DeMarco R, Navarro MVAS, Risi C, Galkin VE, Garratt RC, Araújo APU. Filaments and fingers: Novel structural aspects of the single septin from Chlamydomonas reinhardtii. J Biol Chem. 2017;292:10899–911. doi.org/10.1074/jbc.M116.762229

Structural study on the single septin from the algae Chlamydomonas reinhardtii (CrSEPT), an interesting model to study homofilament formation. We describe a catalytic arginine-finger, which accelerates the hydrolytic rate of the GTP.

20. Valadares NF, Pereira HM, Araújo APU,  Garratt RC. Septin structure and filament assembly. Biophys Rev. 2017;9:481–500. doi.org/10.1007/s12551-017-0320-4

Our first review on the structural aspect of septins.

19. Zeraik AE, Staykova M, Fontes MG, Nemuraitė I, Quinlan R, Araújo APU, DeMarco R. Biophysical dissection of schistosome septins: Insights into oligomerization and membrane binding. Biochimie. 2016;131:96–105. doi.org/10.1016/j.biochi.2016.09.014

18. Valadares NF, Garratt RC. Septin crystallization for structural analysis. Methods Cell Biol. 2016;136:321–38. doi.org/10.1016/bs.mcb.2016.03.017

Review on the effective production of septin samples for structural studies.

17. Sala FA, Valadares NF, Macedo JNA, Borges JC, Garratt RC. Heterotypic coiled-coil formation is essential for the correct assembly of the septin heterofilament. Biophys J. 2016;111:2608–19. doi.org/10.1016/j.bpj.2016.10.032

16. Ortore MG, Macedo JNA, Araújo APU, Ferrero C, Mariani P, Spinozzi F, Itri R. Structural and thermodynamic properties of septin 3 investigated by small-angle X-ray scattering. Biophys J. 2015;108:2896–902. doi.org/10.1016/j.bpj.2015.05.015

15. Zeraik AE, Galkin VE, Rinaldi G, Garratt RC, Smout MJ, Loukas A, Mann VH, Araújo APU, DeMarco R, Brindley PJ. Reversible paralysis of Schistosoma mansoni by forchlorfenuron, a phenylurea cytokinin that affects septins. Int J Parasitol. 2014;44:523–31. doi.org/10.1016/j.ijpara.2014.03.010

14. Zeraik AE, Pereira HM, Santos YV, Brandão-Neto J, Spoerner M, Santos MS, Colnago LA, Garratt RC, Araújo APU, DeMarco R. Crystal structure of a Schistosoma mansoni septin reveals the phenomenon of strand slippage in septins dependent on the nature of the bound nucleotide. J Biol Chem. 2014;289:7799–811. doi.org/10.1074/jbc.M113.525352

13. Damalio JCP, Nobre TM, Lopes JL, Oliveira Jr ON, Araújo APU. Lipid interaction triggering Septin2 to assembly into β-sheet structures investigated by Langmuir monolayers and PM-IRRAS. Biochim Biophys Acta (BBA)-Biomembranes. 2013;1828:1441–8. doi.org/10.1016/j.bbamem.2013.02.003

12. Zeraik AE, Rinaldi G, Mann VH, Popratiloff A, Araújo APU, DeMarco R, Brindley PJ. Septins of platyhelminths: identification, phylogeny, expression and localization among developmental stages of Schistosoma mansoni. PLoS Negl Trop Dis. 2013;7:e2602. doi.org/10.1371%2Fjournal.pntd.0002602

11. Macedo JNA, Valadares NF, Marques IA, Ferreira FM, Damalio JCP, Pereira HM, Garratt RC, Araújo APU. On the Structural and Biochemical Properties of the Human Septins: SEPT3. Biophys J. 2013;104:567a. doi.org/10.1016/j.bpj.2012.11.3144

10. Macedo JNA, Valadares NF, Marques IA, Ferreira FM, Damalio JCP, Pereira HM, Garratt RC, Araújo APU. The structure and properties of septin 3: a possible missing link in septin filament formation. Biochem J. 2013;450:95–105. doi.org/10.1042/BJ20120851

First structural description of a SEPT3-group member (SEPT3 at 2.88 Å resolution).

9. Damalio JCP, Garcia W, Macedo JNA, Marques I de A, Andreu JM, Giraldo R, Garratt RC, Araújo APU. Self assembly of human septin 2 into amyloid filaments. Biochimie. 2012;94:628–36. doi.org/10.1016/j.biochi.2011.09.014

8. Marques I de A, Valadares NF, Garcia W, Damalio JCP, Macedo JNA, Araújo APU, Botello CA, Andreu JM, Garratt RC. Septin C-terminal domain interactions: implications for filament stability and assembly. Cell Biochem Biophys. 2012;62:317–28. doi.org/10.1007/s12013-011-9307-0

7. Itri R, Sales EM, Damalio JCP, de Souza Barbosa LR, Araújo APU. Structural Studies of Septin 2 in Solution. Biophys J. 2011;100:375a. doi.org/10.1016/j.bpj.2010.12.2237

6. Serrão VHB, Alessandro F, Caldas VEA, Marçal RL, Pereira HM, Thiemann OH, Garratt RC. Promiscuous interactions of human septins: the GTP binding domain of SEPT7 forms filaments within the crystal. Febs Lett. 2011;585:3868–73. doi.org/10.1016/j.febslet.2011.10.043

Article of our first solved septin structure (SEPT7 at 3.35 Å resolution).

5. Nakahira M, Macedo JNA, Seraphim TV, Cavalcante N,Souza TACB, Damalio JCP, Reyes LF, Assmann EM, Alborghetti MR, Garratt RC, Araújo APU, Zanchin NIT, Barbosa JARG, Kobarg J. A draft of the human septin interactome. PLoS One. 2010;5:13799. doi.org/10.1371/journal.pone.0013799

Most cited paper from our group so far. Results of yeast two-hybrid screens with human septins 1–10. Among the partners detected, we found mainly other septins, confirming that septins form homo- and heteropolymeric filaments.

4. Garcia W, Rodrigues NC, de Oliveira Neto M, Araújo APU, Polikarpov I, Tanaka M, Tanaka T, Garratt RC. The stability and aggregation properties of the GTPase domain from human SEPT4. Biochim Biophys Acta (BBA)-Proteins Proteomics. 2008;1784:1720–7. doi.org/10.1016/j.bbapap.2008.06.005

3. Garcia W, Araújo APU, Lara F, Foguel D, Tanaka M, Tanaka T, Garratt RC. An intermediate structure in the thermal unfolding of the GTPase domain of human septin 4 (SEPT4/Bradeion-β) forms amyloid-like filaments in vitro. Biochemistry. 2007;46:11101–9. doi.org/10.1021/bi700702w

2. Garcia W, Araújo APU, de Oliveira Neto M, Ballestero MRM, Polikarpov I, Tanaka M, Tanaka T, Garratt RC. Dissection of a human septin: definition and characterization of distinct domains within human SEPT4. Biochemistry. 2006;45:13918–31. doi.org/10.1021/bi061549z

1.  Hillebrand S, Garcia W, Cantú MD, Araújo APU, Tanaka M, Tanaka T, Garratt RC, Carrilho E. In vitro monitoring of GTPase activity and enzyme kinetics studies using capillary electrophoresis. Anal Bioanal Chem. 2005;383:92–7. doi.org/10.1007/s00216-005-3375-1