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- Title
MamK, a bacterial actin, forms dynamic filaments in vivo that are regulated by the acidic proteins MamJ and LimJ.
- Authors
Draper, Olga; Byrne, Meghan E.; Li, Zhuo; Keyhani, Sepehr; Barrozo, Joyce Cueto; Jensen, Grant; Komeili, Arash
- Abstract
Summary Bacterial actins, in contrast to their eukaryotic counterparts, are highly divergent proteins whose wide-ranging functions are thought to correlate with their evolutionary diversity. One clade, represented by the MamK protein of magnetotactic bacteria, is required for the subcellular organization of magnetosomes, membrane-bound organelles that aid in navigation along the earth's magnetic field. Using a fluorescence recovery after photobleaching assay in Magnetospirillum magneticum AMB-1, we find that, like traditional actins, MamK forms dynamic filaments that require an intact NTPase motif for their turnover in vivo. We also uncover two proteins, MamJ and LimJ, which perform a redundant function to promote the dynamic behaviour of MamK filaments in wild-type cells. The absence of both MamJ and LimJ leads to static filaments, a disrupted magnetosome chain, and an anomalous build-up of cytoskeletal filaments between magnetosomes. Our results suggest that MamK filaments, like eukaryotic actins, are intrinsically stable and rely on regulators for their dynamic behaviour, a feature that stands in contrast to some classes of bacterial actins characterized to date.
- Subjects
ACTIN; EUKARYOTIC cells; PROTEINS; MAGNETOTACTIC bacteria; MAGNETOSOMES; ORGANELLES
- Publication
Molecular Microbiology, 2011, Vol 82, Issue 2, p342
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/j.1365-2958.2011.07815.x