Dataset Information

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals.

ABSTRACT: The magnetosome is an organelle specialized for inorganic magnetite crystal synthesis in magnetotactic bacteria. The complex mechanism of magnetosome formation is regulated by magnetosome proteins in a stepwise manner. Protein localization is a key step for magnetosome development; however, a global study of magnetosome protein localization remains to be conducted. Here, we comparatively analyzed the subcellular localization of a series of green fluorescent protein (GFP)-tagged magnetosome proteins. The protein localizations were categorized into 5 groups (short-length linear, middle-length linear, long-length linear, cell membrane, and intracellular dispersing), which were related to the protein functions. Mms6, which regulates magnetite crystal growth, localized along magnetosome chain structures under magnetite-forming (microaerobic) conditions but was dispersed in the cell under nonforming (aerobic) conditions. Correlative fluorescence and electron microscopy analyses revealed that Mms6 preferentially localized to magnetosomes enclosing magnetite crystals. We suggest that a highly organized spatial regulation mechanism controls magnetosome protein localization during magnetosome formation in magnetotactic bacteria.Magnetotactic bacteria synthesize magnetite (Fe3O4) nanocrystals in a prokaryotic organelle called the magnetosome. This organelle is formed using various magnetosome proteins in multiple steps, including vesicle formation, magnetosome alignment, and magnetite crystal formation, to provide compartmentalized nanospaces for the regulation of iron concentrations and redox conditions, enabling the synthesis of a morphologically controlled magnetite crystal. Thus, to rationalize the complex organelle development, the localization of magnetosome proteins is considered to be highly regulated; however, the mechanisms remain largely unknown. Here, we performed comparative localization analysis of magnetosome proteins that revealed the presence of a spatial regulation mechanism within the linear structure of magnetosomes. This discovery provides evidence of a highly regulated protein localization mechanism for this bacterial organelle development.

SUBMITTER: Arakaki A

PROVIDER: S-EPMC5038011 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals.

Arakaki Atsushi A Kikuchi Daiki D Tanaka Masayoshi M Yamagishi Ayana A Yoda Takuto T Matsunaga Tadashi T

Journal of bacteriology 20160922 20

<h4>Unlabelled</h4>The magnetosome is an organelle specialized for inorganic magnetite crystal synthesis in magnetotactic bacteria. The complex mechanism of magnetosome formation is regulated by magnetosome proteins in a stepwise manner. Protein localization is a key step for magnetosome development; however, a global study of magnetosome protein localization remains to be conducted. Here, we comparatively analyzed the subcellular localization of a series of green fluorescent protein (GFP)-tagge ...[more]

PMID: 27481925

Similar Datasets

Project description:Magnetospirillum gryphiswaldense and related magnetotactic bacteria form magnetosomes, which are membrane-enclosed organelles containing crystals of magnetite (Fe3O4) that cause the cells to orient in magnetic fields. The characteristic sizes, morphologies, and patterns of alignment of magnetite crystals are controlled by vesicles formed of the magnetosome membrane (MM), which contains a number of specific proteins whose precise roles in magnetosome formation have remained largely elusive. Here, we report on a functional analysis of the small hydrophobic MamGFDC proteins, which altogether account for nearly 35% of all proteins associated with the MM. Although their high levels of abundance and conservation among magnetotactic bacteria had suggested a major role in magnetosome formation, we found that the MamGFDC proteins are not essential for biomineralization, as the deletion of neither mamC, encoding the most abundant magnetosome protein, nor the entire mamGFDC operon abolished the formation of magnetite crystals. However, cells lacking mamGFDC produced crystals that were only 75% of the wild-type size and were less regular than wild-type crystals with respect to morphology and chain-like organization. The inhibition of crystal formation could not be eliminated by increased iron concentrations. The growth of mutant crystals apparently was not spatially constrained by the sizes of MM vesicles, as cells lacking mamGFDC formed vesicles with sizes and shapes nearly identical to those formed by wild-type cells. However, the formation of wild-type-size magnetite crystals could be gradually restored by in-trans complementation with one, two, and three genes of the mamGFDC operon, regardless of the combination, whereas the expression of all four genes resulted in crystals exceeding the wild-type size. Our data suggest that the MamGFDC proteins have partially redundant functions and, in a cumulative manner, control the growth of magnetite crystals by an as-yet-unknown mechanism.

Dataset Information

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals.

Publications

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets