7m6j

From Proteopedia

(Difference between revisions)

Current revision

Human Septin Hexameric Complex SEPT2G/SEPT6/SEPT7 by Single Particle Cryo-EM

Structural highlights

7m6j is a 6 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.6Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SEPT2_HUMAN Filament-forming cytoskeletal GTPase. Required for normal organization of the actin cytoskeleton. Plays a role in the biogenesis of polarized columnar-shaped epithelium by maintaining polyglutamylated microtubules, thus facilitating efficient vesicle transport, and by impeding MAP4 binding to tubulin. Required for the progression through mitosis. Forms a scaffold at the midplane of the mitotic splindle required to maintain CENPE localization at kinetochores and consequently chromosome congression. During anaphase, may be required for chromosome segregation and spindle elongation. Plays a role in ciliogenesis and collective cell movements. In cilia, required for the integrity of the diffusion barrier at the base of the primary cilium that prevents diffusion of transmembrane proteins between the cilia and plasma membranes: probably acts by regulating the assembly of the tectonic-like complex (also named B9 complex) by localizing TMEM231 protein. May play a role in the internalization of 2 intracellular microbial pathogens, Listeria monocytogenes and Shigella flexneri.^[1] ^[2] ^[3] ^[4]

Publication Abstract from PubMed

In order to form functional filaments, human septins must assemble into hetero-oligomeric rod-like particles which polymerize end-to-end. The rules governing the assembly of these particles and the subsequent filaments are incompletely understood. Although crystallographic approaches have been successful in studying the separate components of the system, there has been difficulty in obtaining high resolution structures of the full particle. Here we report a first cryo-EM structure for a hexameric rod composed of human septins 2, 6 and 7 with a global resolution of ~3.6 A and a local resolution of between ~3.0 A and ~5.0 A. By fitting the previously determined high-resolution crystal structures of the component subunits into the cryo-EM map, we are able to provide an essentially complete model for the particle. This exposes SEPT2 NC-interfaces at the termini of the hexamer and leaves internal cavities between the SEPT6-SEPT7 pairs. The floor of the cavity is formed by the two alpha(0) helices including their polybasic regions. These are locked into place between the two subunits by interactions made with the alpha(5) and alpha(6) helices of the neighbouring monomer together with its polyacidic region. The cavity may serve to provide space allowing the subunits to move with respect to one another. The elongated particle shows a tendency to bend at its centre where two copies of SEPT7 form a homodimeric G-interface. Such bending is almost certainly related to the ability of septin filaments to recognize and even induce membrane curvature.

An atomic model for the human septin hexamer by cryo-EM.,Mendonca DC, Guimaraes SL, Pereira HD, Pinto AA, de Farias MA, de Godoy AS, Araujo APU, van Heel M, Portugal RV, Garratt RC J Mol Biol. 2021 Jul 23;433(15):167096. doi: 10.1016/j.jmb.2021.167096. Epub 2021 , Jun 9. PMID:34116125^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Spiliotis ET, Kinoshita M, Nelson WJ. A mitotic septin scaffold required for Mammalian chromosome congression and segregation. Science. 2005 Mar 18;307(5716):1781-5. PMID:15774761 doi:http://dx.doi.org/10.1126/science.1106823
↑ Kremer BE, Adang LA, Macara IG. Septins regulate actin organization and cell-cycle arrest through nuclear accumulation of NCK mediated by SOCS7. Cell. 2007 Sep 7;130(5):837-50. PMID:17803907 doi:http://dx.doi.org/10.1016/j.cell.2007.06.053
↑ Spiliotis ET, Hunt SJ, Hu Q, Kinoshita M, Nelson WJ. Epithelial polarity requires septin coupling of vesicle transport to polyglutamylated microtubules. J Cell Biol. 2008 Jan 28;180(2):295-303. doi: 10.1083/jcb.200710039. Epub 2008, Jan 21. PMID:18209106 doi:http://dx.doi.org/10.1083/jcb.200710039
↑ Mostowy S, Nam Tham T, Danckaert A, Guadagnini S, Boisson-Dupuis S, Pizarro-Cerda J, Cossart P. Septins regulate bacterial entry into host cells. PLoS One. 2009;4(1):e4196. doi: 10.1371/journal.pone.0004196. Epub 2009 Jan 15. PMID:19145258 doi:http://dx.doi.org/10.1371/journal.pone.0004196
↑ Mendonça DC, Guimarães SL, Pereira HD, Pinto AA, de Farias MA, de Godoy AS, Araujo APU, van Heel M, Portugal RV, Garratt RC. An atomic model for the human septin hexamer by cryo-EM. J Mol Biol. 2021 Jul 23;433(15):167096. PMID:34116125 doi:10.1016/j.jmb.2021.167096

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/7m6j"

@@ Line 1: / Line 1: @@
-====
+==Human Septin Hexameric Complex SEPT2G/SEPT6/SEPT7 by Single Particle Cryo-EM==
-<StructureSection load='7m6j' size='340' side='right'caption='[[7m6j]]' scene=''>
+<StructureSection load='7m6j' size='340' side='right'caption='[[7m6j]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
 == Structural highlights ==
-<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id= OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol= FirstGlance]. <br>
+<table><tr><td colspan='2'>[[7m6j]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7M6J OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7M6J FirstGlance]. <br>
-</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7m6j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7m6j OCA], [https://pdbe.org/7m6j PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7m6j RCSB], [https://www.ebi.ac.uk/pdbsum/7m6j PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7m6j ProSAT]</span></td></tr>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.6&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7m6j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7m6j OCA], [https://pdbe.org/7m6j PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7m6j RCSB], [https://www.ebi.ac.uk/pdbsum/7m6j PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7m6j ProSAT]</span></td></tr>
 </table>
+== Function ==
+[https://www.uniprot.org/uniprot/SEPT2_HUMAN SEPT2_HUMAN] Filament-forming cytoskeletal GTPase. Required for normal organization of the actin cytoskeleton. Plays a role in the biogenesis of polarized columnar-shaped epithelium by maintaining polyglutamylated microtubules, thus facilitating efficient vesicle transport, and by impeding MAP4 binding to tubulin. Required for the progression through mitosis. Forms a scaffold at the midplane of the mitotic splindle required to maintain CENPE localization at kinetochores and consequently chromosome congression. During anaphase, may be required for chromosome segregation and spindle elongation. Plays a role in ciliogenesis and collective cell movements. In cilia, required for the integrity of the diffusion barrier at the base of the primary cilium that prevents diffusion of transmembrane proteins between the cilia and plasma membranes: probably acts by regulating the assembly of the tectonic-like complex (also named B9 complex) by localizing TMEM231 protein. May play a role in the internalization of 2 intracellular microbial pathogens, Listeria monocytogenes and Shigella flexneri.<ref>PMID:15774761</ref> <ref>PMID:17803907</ref> <ref>PMID:18209106</ref> <ref>PMID:19145258</ref>
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+In order to form functional filaments, human septins must assemble into hetero-oligomeric rod-like particles which polymerize end-to-end. The rules governing the assembly of these particles and the subsequent filaments are incompletely understood. Although crystallographic approaches have been successful in studying the separate components of the system, there has been difficulty in obtaining high resolution structures of the full particle. Here we report a first cryo-EM structure for a hexameric rod composed of human septins 2, 6 and 7 with a global resolution of ~3.6 A and a local resolution of between ~3.0 A and ~5.0 A. By fitting the previously determined high-resolution crystal structures of the component subunits into the cryo-EM map, we are able to provide an essentially complete model for the particle. This exposes SEPT2 NC-interfaces at the termini of the hexamer and leaves internal cavities between the SEPT6-SEPT7 pairs. The floor of the cavity is formed by the two alpha(0) helices including their polybasic regions. These are locked into place between the two subunits by interactions made with the alpha(5) and alpha(6) helices of the neighbouring monomer together with its polyacidic region. The cavity may serve to provide space allowing the subunits to move with respect to one another. The elongated particle shows a tendency to bend at its centre where two copies of SEPT7 form a homodimeric G-interface. Such bending is almost certainly related to the ability of septin filaments to recognize and even induce membrane curvature.
+An atomic model for the human septin hexamer by cryo-EM.,Mendonca DC, Guimaraes SL, Pereira HD, Pinto AA, de Farias MA, de Godoy AS, Araujo APU, van Heel M, Portugal RV, Garratt RC J Mol Biol. 2021 Jul 23;433(15):167096. doi: 10.1016/j.jmb.2021.167096. Epub 2021 , Jun 9. PMID:34116125<ref>PMID:34116125</ref>
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
+</div>
+<div class="pdbe-citations 7m6j" style="background-color:#fffaf0;"></div>
+== References ==
+<references/>
 __TOC__
 </StructureSection>
+[[Category: Homo sapiens]]
 [[Category: Large Structures]]
-[[Category: Z-disk]]
+[[Category: Garratt RC]]
+[[Category: Mendonca DC]]
+[[Category: Pereira HM]]
+[[Category: Portugal RV]]
+[[Category: Van Heel M]]

7m6j

From Proteopedia

Current revision

Human Septin Hexameric Complex SEPT2G/SEPT6/SEPT7 by Single Particle Cryo-EM

Structural highlights

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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