Skip to Main content Skip to Navigation
Journal articles

Loss of the actin-like protein MamK has pleiotropic effects on magnetosome formation and chain assembly in Magnetospirillum gryphiswaldense

Abstract : Magnetotactic bacteria synthesize magnetosomes, which are unique organelles consisting of membrane-enclosed magnetite crystals. For magnetic orientation individual magnetosome particles are assembled into well-organized chains. The actin-like MamK and the acidic MamJ proteins were previously implicated in chain assembly. While MamK was suggested to form magnetosome-associated cytoskeletal filaments, MamJ is assumed to attach the magnetosome vesicles to these structures. Although the deletion of either mamK in M. magneticum, or mamJ in M. gryphiswaldense affected chain formation, the previously observed phenotypes were not fully consistent, suggesting different mechanisms of magnetosome chain assembly in both organisms. Here we show that in M. gryphiswaldense MamK is not absolutely required for chain formation. Straight chains, shorter, fragmented, and ectopic, were still formed in a mamK deletion mutant, although magnetosome filaments were absent as shown by cryo-electron tomography. Loss of MamK also resulted in reduced numbers of magnetite crystals and magnetosome vesicles and led to the mislocalization of MamJ. In addition, extensive analysis of wildtype and mutant cells revealed previously unidentified ultrastructural characteristics in M. gryphiswaldense. Our results suggest that, despite of their functional equivalence, loss of MamK proteins in different bacteria may result in distinct phenotypes, which might be due to a species-specific genetic context.
Mots-clés : Life Sciences
Document type :
Journal articles
Complete list of metadata

Cited literature [28 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-00552637
Contributor : Hal Peer <>
Submitted on : Thursday, January 6, 2011 - 4:00:54 AM
Last modification on : Thursday, February 7, 2019 - 4:03:18 PM
Long-term archiving on: : Friday, December 2, 2016 - 11:50:40 PM

File

PEER_stage2_10.1111%2Fj.1365-2...
Files produced by the author(s)

Identifiers

Collections

Citation

Emanuel Katzmann, André Scheffel, Manuela Gruska, Jürgen M Plitzko, Dirk Schüler. Loss of the actin-like protein MamK has pleiotropic effects on magnetosome formation and chain assembly in Magnetospirillum gryphiswaldense. Molecular Microbiology, Wiley, 2010, ⟨10.1111/j.1365-2958.2010.07202.x⟩. ⟨hal-00552637⟩

Share

Metrics

Record views

365

Files downloads

470