Structural highlights
Function
SEPT6_HUMAN Filament-forming cytoskeletal GTPase. Required for normal organization of the actin cytoskeleton. Involved in cytokinesis. May play a role in HCV RNA replication.[1] [2]
Publication Abstract from PubMed
The assembly of a septin filament requires that homologous monomers must distinguish between one another in establishing appropriate interfaces with their neighbors. To understand this phenomenon at the molecular level, we present the first four crystal structures of heterodimeric septin complexes. We describe in detail the two distinct types of G-interface present within the octameric particles, which must polymerize to form filaments. These are formed between SEPT2 and SEPT6 and between SEPT7 and SEPT3, and their description permits an understanding of the structural basis for the selectivity necessary for correct filament assembly. By replacing SEPT6 by SEPT8 or SEPT11, it is possible to rationalize Kinoshita'spostulate, which predicts the exchangeability of septins from within a subgroup. Switches I and II, which in classical small GTPases provide a mechanism for nucleotide-dependent conformational change, have been repurposed in septins to play a fundamental role in molecular recognition. Specifically, it is switch I which holds the key to discriminating between the two different G-interfaces. Moreover, residues which are characteristic for a given subgroup play subtle, but pivotal, roles in guaranteeing that the correct interfaces are formed.
Molecular Recognition at Septin Interfaces: The Switches Hold the Key.,Rosa HVD, Leonardo DA, Brognara G, Brandao-Neto J, D'Muniz Pereira H, Araujo APU, Garratt RC J Mol Biol. 2020 Sep 7. pii: S0022-2836(20)30531-3. doi:, 10.1016/j.jmb.2020.09.001. PMID:32910969[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ 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:https://dx.doi.org/10.1016/j.cell.2007.06.053
- ↑ Kim CS, Seol SK, Song OK, Park JH, Jang SK. An RNA-binding protein, hnRNP A1, and a scaffold protein, septin 6, facilitate hepatitis C virus replication. J Virol. 2007 Apr;81(8):3852-65. Epub 2007 Jan 17. PMID:17229681 doi:https://dx.doi.org/10.1128/JVI.01311-06
- ↑ Rosa HVD, Leonardo DA, Brognara G, Brandão-Neto J, D'Muniz Pereira H, Araújo APU, Garratt RC. Molecular Recognition at Septin Interfaces: The Switches Hold the Key. J Mol Biol. 2020 Oct 2;432(21):5784-5801. PMID:32910969 doi:10.1016/j.jmb.2020.09.001
