Prokaryotic origin of the actin cytoskeleton

  title={Prokaryotic origin of the actin cytoskeleton},
  author={Fusinita van den Ent and Linda A Amos and Jan L{\"o}we},
It was thought until recently that bacteria lack the actin or tubulin filament networks that organize eukaryotic cytoplasm. However, we show here that the bacterial MreB protein assembles into filaments with a subunit repeat similar to that of F-actin—the physiological polymer of eukaryotic actin. By elucidating the MreB crystal structure we demonstrate that MreB and actin are very similar in three dimensions. Moreover, the crystals contain protofilaments, allowing visualization of actin-like… 

The Bacterial Actin-Like Cytoskeleton

The dynamic prokaryotic actin-like cytoskeleton is thought to serve as a central organizer for the targeting and accurate positioning of proteins and nucleoprotein complexes, thereby (and by analogy to the eukaryotic cytos skeleton) spatially and temporally controlling macromolecular trafficking in bacterial cells.

Cytoskeleton: The missing link

  • A. Schuldt
  • Biology
    Nature Reviews Molecular Cell Biology
  • 2001
Two papers from Cell and Nature uncover the prokaryotic ancestor of actin — MreB, which does not tend to form helical protofilaments like eukaryotic actin but is straighter, contesting the long-held belief that the natural shape ofActin is helical.


■ Abstract The structural elucidation of clear but distant homologs of actin and tubulin in bacteria and GFP labeling of these proteins promises to reinvigorate the field of prokaryotic cell biology.

Bacterial actin MreB assembles in complex with cell shape protein RodZ

It is shown that the cytoplasmic helix‐turn‐helix motif of Thermotoga maritima RodZ directly interacts with monomeric as well as filamentous MreB and the crystal structure of the complex is presented, which elucidate how the bacterial actin cytoskeleton might be anchored to the membrane to help constrain peptidoglycan synthesis in the periplasm.

eview volution of cytomotive filaments : The cytoskeleton from prokaryotes o eukaryotes

Prokaryotes appear to have a third class of cytomotive filaments, typically associated with surfaces such as membranes or DNA: Walker A cytoskeletal ATPases (WACA).

Structural complexity of filaments formed from the actin and tubulin folds

The history of the structure determination of the eukaryotic actin filament is reviewed to give a sense of context for the discovery of the new ParM filament structures, and the novel ParM geometries are described and it is predicted that even more complex actin-like filaments may exist in bacteria.

F‐actin‐like filaments formed by plasmid segregation protein ParM

It is shown here that ParM polymerizes into double helical protofilaments with a longitudinal repeat similar to filamentous actin (F‐actin) and MreB filaments that maintain the cell shape of non‐spherical bacteria.

New insights into the mechanisms of cytomotive actin and tubulin filaments.




An atomic model of crystalline actin tubes: combining electron microscopy with X-ray crystallography.

An integrated structural approach which combines intermediate resolution electron microscopy based 3-D reconstruction and surface metal shadowing of crystalline actin tubes with atomic resolution X-ray data of the G-actin monomer is chosen.

Crystal structure of the cell division protein FtsA from Thermotoga maritima

Elucidation of the crystal structure of FtsA shows that another bacterial protein involved in cytokinesis is structurally related to a eukaryotic cytoskeletalprotein involved in inflammation.

Tubulin and FtsZ form a distinct family of GTPases

The highly conserved nucleotide-binding sites of tubulin and FtsZ clearly differ from those of EF-Tu and other GTPases, while resembling the nucleotide site of glyceraldehyde-3-phosphate dehydrogenase, indicating a distinct family of GTP-hydrolyzing proteins.

Atomic structure of the actin: DNase I complex

The atomic models of the complex between rabbit skeletal muscle actin and bovine pancreatic deoxyribonuclease I both in the ATP and ADP forms have been determined byo X-ray analysis at an effective

Domain motions in actin.

This work confirms predictions about the nature of the domain rotation in actin based on its structural similarity to hexokinase and shows that residues at the interface between the two rigid cores undergo a shear between alternative conformations of actin.

The actin fold

  • W. KabschK. Holmes
  • Biology
    FASEB journal : official publication of the Federation of American Societies for Experimental Biology
  • 1995
X‐ray structure analysis of actin and of the NH2‐terminal domain of the heat‐shock cognate protein Hsc70 has revealed an unexpected extensive structural similarity between these two molecules, suggesting that the molecules may have evolved by gene duplication.

The structure of an open state of beta-actin at 2.65 A resolution.

Applying osmotic pressure to profilin:beta-actin crystals brings about a collapse of the unit cell comparable with that seen in the open to tight-state transition, enabling an estimate of the work required to cause this transformation of beta- actin in the crystals.

Similarity of the three-dimensional structures of actin and the ATPase fragment of a 70-kDa heat shock cognate protein.

A local sequence "fingerprint," which may be diagnostic of the adenine nucleotide beta-phosphate-binding pocket, has been derived and identifies members of the glycerol kinase family as candidates likely to have a similar structure in their nucleotide-binding domains.