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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A revised order of subunits in mammalian septin complexes

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Mendonca, Deborah C. [1] ; Macedo, Joci N. [1, 2] ; Guimaraes, Samuel L. [1] ; Barroso da Silva, Fernando L. [3, 4] ; Cassago, Alexandre [5] ; Garratt, Richard C. [1] ; Portugal, Rodrigo V. [5] ; Araujo, Ana P. U. [1]
Total Authors: 8
[1] Univ Sao Paulo, Sao Carlos Inst Phys, Sao Carlos, SP - Brazil
[2] Fed Inst Educ Sci & Technol Rondonia, Vilhena - Brazil
[3] Univ Sao Paulo, Fac Pharmaceut Sci, Ribeirao Preto, SP - Brazil
[4] Univ Paris Diderot, UMR S 1134, Paris - France
[5] CNPEM, Brazilian Nanotechnol Natl Lab, Campinas, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: CYTOSKELETON; v. 76, n. 9-10, p. 457-466, SEP 2019.
Web of Science Citations: 0

Septins are GTP binding proteins considered to be novel components of the cytoskeleton. They polymerize into filaments based on hexameric or octameric core particles in which two copies of either three or four different septins, respectively, assemble into a specific sequence. Viable combinations of the 13 human septins are believed to obey substitution rules in which the different septins involved must come from distinct subgroups. The hexameric assembly, for example, has been reported to be SEPT7-SEPT6-SEPT2-SEPT2-SEPT6-SEPT7. Here, we have replaced SEPT2 by SEPT5 according to the substitution rules and used transmission electron microscopy to demonstrate that the resulting recombinant complex assembles into hexameric particles which are inverted with respect that predicted previously. MBP-SEPT5 constructs and immunostaining show that SEPT5 occupies the terminal positions of the hexamer. We further show that this is also true for the assembly including SEPT2, in direct contradiction with that reported previously. Consequently, both complexes expose an NC interface, as reported for yeast, which we show to be more susceptible to high salt concentrations. The correct assembly for the canonical combination of septins 2-6-7 is therefore established to be SEPT2-SEPT6-SEPT7-SEPT7-SEPT6-SEPT2, implying the need for revision of the mechanisms involved in filament assembly. (AU)

FAPESP's process: 15/16116-3 - Molecular mechanisms of electrostatic origin responsible for protein complexation
Grantee:Fernando Luis Barroso da Silva
Support type: Regular Research Grants
FAPESP's process: 14/15546-1 - Septins: comparative studies and the correlation between structure and function
Grantee:Richard Charles Garratt
Support type: Research Projects - Thematic Grants
FAPESP's process: 17/15340-2 - EMU: acquisition of a transmission electron microscope for single particle cryo electron microscopy - establishing a cryo electron microscopy open facility at CNPEM
Grantee:Rodrigo Villares Portugal
Support type: Multi-user Equipment Program