Structure and Dynamics of Actin-Like Cytomotive Filaments in Plasmid Segregation

Abstract

One of the well-known functions of the bacterial cytoskeleton is plasmid segregation. Type II plasmid segregation systems, among the best characterized with respect to the mechanism of action, possess an actin-like cytomotive filament as the motor component. This chapter describes the essential components of the plasmid segregation machinery and their mechanism of action, concentrating on the actin-like protein family of the bacterial cytoskeleton. The structures of the actin-like filaments depend on their nucleotide state and these in turn contribute to the dynamics of the filaments. The components that link the filaments to the plasmid DNA also regulate filament dynamics. The modulation of the dynamics facilitates the cytomotive filament to function as a mitotic spindle with a minimal number of components.

Two co‐dominant nitrogen‐fixing cyanobacteria demonstrate distinct acclimation and adaptation responses to cope with ocean warming

“…As self‐replicating, extra‐chromosomal genetic materials, plasmids can also facilitate the adaptation of bacteria to environmental stress (Leplae et al ., 2006; Heuer and Smalla, 2012). To ensure equal inheritance of plasmids by daughter cells during cell division, bacterial plasmids encode efficient plasmid partitioning machineries, such as the ParMRC system (Gayathri and Harne, 2017). These actin‐like proteins are responsible for segregating large DNA plasmids by forming filaments and pushing two sister plasmids towards two opposing poles, together with ParRC complexes (Salje et al ., 2010; Gayathri et al ., 2012).…”

“…plasmids encode efficient plasmid partitioning machineries, such as the ParMRC system (Gayathri and Harne, 2017). These actin-like proteins are responsible for segregating large DNA plasmids by forming filaments and pushing two sister plasmids towards two opposing poles, together with ParRC complexes (Salje et al, 2010;Gayathri et al, 2012).…”

Subcellular Organization: A Critical Feature of Bacterial Cell Replication

“…In rod-shaped bacteria, one way to ensure inheritance of a low-copy-number factor upon division is by segregating copies to opposite ends of the cell. This strategy is used by a subset of low-copy-number plasmids whose segregation mechanisms are based on active transport and dynamic cytoskeletal filaments made of distant actin or tubulin homologs (Fink and Aylett, 2017; Gayathri and Harne, 2017). This is illustrated by the ParM/R system encoded by the low-copy-number E. coli plasmid R1 (Moller-Jensen et al, 2003).…”