#bacterial cytoskeleton

Microbial Physiology

The MreB cytoskeletal protein plays a role in:

MreB is a widely distributed bacterial homolog of eukaryotic actin conserved across rod-shaped bacteria including Escherichia coli, Bacillus subtilis, and Caulobacter crescentus, essential for maintaining cylindrical morphology and coordinating growth. Unlike eukaryotic actin that forms long helical filaments, MreB assembles into short, antiparallel double protofilaments associated with inner face of cytoplasmic membrane in an ATP-dependent manner, often guided by membrane regions enriched in specific phospholipids. Its primary morphogenetic function is to act as a dynamic scaffold organizing

Ref: Burkman et al., Ann Rev Microbiol 2018, MreB and Rod Shape; Errington, Nature Rev Microbiol 2015, Bacterial Cytoskeleton.

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Microbial Physiology

The cytoskeletal protein MamK is involved in:

Magnetotactic bacteria such as Magnetospirillum magneticum AMB-1 and gryphiswaldense biomineralize magnetic nanoparticles within lipid vesicles called magnetosomes to navigate chemical gradients in stratified water columns. Cytoskeletal protein MamK actin homolog is essential for organizing magnetosomes into linear chain maximizing dipole moment for efficient orientation. MamK polymerizes ATP dependently into filaments extending along cell long axis, forms scaffold similar MreB but dedicated. Adaptor protein MamJ interacts with magnetosome membrane proteins MamY and MamK linking vesicles to fi

Ref: Komeili et al., PNAS 2006, MamK involved in magnetosome positioning chain assembly.

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Microbial Physiology

The Elongasome in rod-shaped bacteria is primarily composed of:

In rod shaped bacteria elongation before division mediated by elongasome or Rod complex distinct from divisome. Core organizer is MreB actin homolog that forms short dynamic patches moving around cell circumference perpendicular to long axis. Motion driven by peptidoglycan synthesis not treadmilling alone, powered by RodA transglycosylase activity. MreB interacts with integral membrane proteins MreC, MreD, RodZ cytoplasmic tail linking to peptidoglycan synthases RodA transglycosylase from SEDS family polymerizing lipid II glycan strands and PBP2a PBP2 transpeptidase crosslinking peptides. Addi

Ref: Shi et al., PNAS 2020, Elongasome - MreB and associated proteins direct lateral wall synthesis.

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Microbial Physiology

Which cytoskeletal protein is responsible for maintaining rod shape in bacteria?

Cell shape maintenance in prokaryotes relies on cytoskeletal elements directing wall synthesis. Rod shape requires lateral peptidoglycan insertion along sidewall producing cylinder with hemispherical poles. MreB is bacterial actin homolog sharing actin fold ATP binding pocket polymerizes into short double filaments moving circumferentially around cell coordinated with cell wall synthesis enzymes. MreB associates with MreC MreD transmembrane proteins and RodZ linking to RodA SEDS transglycosylase and PBP2 transpeptidase elongasome complex synthesizing hoop like glycans inserting along length. D

Ref: Cabeen & Jacobs-Wagner, Annu Rev Genetics, 2010, Bacterial cytoskeleton: MreB maintains rod shape.

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