Biogenesis and subcellular organization of the magnetosome organelles of magnetotactic bacteria

Bacterial cells, like their eukaryotic counterparts, are capable of constructing lipid-based organelles that carry out essential biochemical functions. The magnetosomes of magnetotactic bacteria are one such compartment that is quickly becoming a model for exploring the process of organelle biogenesis in bacteria. Magnetosomes consist of a lipid-bilayer compartment that houses a magnetic crystal. By arranging magnetosomes into chains within the cell, magnetotactic bacteria create an internal compass that is used for navigation along magnetic fields. Over the past decade, a number of studies have elucidated the possible factors involved in the formation of the magnetosome membrane and biomineralization of magnetic minerals. Here, we highlight some of these recent advances with a particular focus on the cell biology of magnetosome formation.

► Magnetosomes are organelles in magnetotactic bacteria containing magnetic minerals.
► The conserved mamAB gene cluster is a central player in magnetosome formation.
► MamI, MamL, MamQ and MamB are required for magnetosome membrane formation.
► MamK, a bacterial actin-like protein, forms filaments organizing magnetosome chains.
► MamK filaments are dynamic in vivo and partially regulated by MamJ and LimJ.