Accessory factors promote AlfA-dependent plasmid segregation by regulating filament nucleation, disassembly, and bundling

作者：Polka Jessica K; Kollman Justin M; Mullins R Dyche^*

来源：Proceedings of the National Academy of Sciences, 2014, 111(6): 2176-2181.

DOI：10.1073/pnas.1304127111

• DNA segregation
• bacterial cytoskeleton
• Bacillus subtilis
• reconstitution

In bacteria, some plasmids are partitioned to daughter cells by assembly of actin-like proteins (ALPs). The best understood ALP, ParM, has a core set of biochemical properties that contributes to its function, including dynamic instability, spontaneous nucleation, and bidirectional elongation. AlfA, an ALP that pushes plasmids apart in Bacillus, relies on a different set of underlying properties to segregate DNA. AlfA elongates unidirectionally and is not dynamically unstable; its assembly and disassembly are regulated by a cofactor, AlfB. Free AlfB breaks up AlfA bundles and promotes filament turnover. However, when AlfB is bound to the centromeric DNA sequence, parN, it forms a segrosome complex that nucleates and stabilizes AlfA filaments. When reconstituted in vitro, this system creates polarized, motile comet tails that associate by antiparallel filament bundling to form bipolar, DNA-segregating spindles.

• 出版日期2014-2-11
• 单位McGill