Magnetosomes are cell membrane invaginations organized by the actin-like protein MamK.

Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. komeili@nature.berkeley.edu

Magnetosomes are membranous bacterial organelles sharing many features of eukaryotic organelles. Using electron cryotomography, we found that magnetosomes are invaginations of the cell membrane flanked by a network of cytoskeletal filaments. The filaments appeared to be composed of MamK, a homolog of the bacterial actin-like protein MreB, which formed filaments in vivo. In a mamK deletion strain, the magnetosome-associated cytoskeleton was absent and individual magnetosomes were no longer organized into chains. Thus, it seems that prokaryotes can use cytoskeletal filaments to position organelles within the cell.

PMID: 16373532 [PubMed - indexed for MEDLINE]