Protein with ATPase activity which forms dynamic cytoplasmic filaments (probably with paralog MamK-like) that organize magnetosomes into long chains running parallel to the long axis of the cell (Probable) (PubMed:21883528, PubMed:28790202, PubMed:23204522, PubMed:24957623). Turnover of MamK filaments is probably promoted by MamK-like, which provides a monomer pool (PubMed:24957623). Forms twisted filaments in the presence of ATP or GTP (PubMed:20161777, PubMed:23204522, PubMed:27391173). Serves to close gaps between magnetosomes in the chain (PubMed:26884433). Interaction with MCP10 is involved in controlling the response to magnetic fields, possibly by controlling flagellar rotation (PubMed:20471399). Expression in E.coli yields a filament in the cell's longitudinal axis; the protein nucleates at several sites and one extremity of the filament is located at the cell pole (PubMed:17085581, PubMed:20161777). ATP + H2O = ADP + H(+) + phosphate Filament turnover is promoted by MamJ and/or LimJ which have overlapping function; at least one other protein is required for turnover. MamK filament dynamics are probably required for the assembly or maintenance of the magnetosome chain. Forms cytoplasmic filaments (PubMed:20471399, PubMed:23204522, PubMed:27821762, PubMed:27391173). Filaments are parallel (polar) and double-helical (PubMed:23204522, PubMed:27821762, PubMed:27391173). MamK subunits from each of the two strands are juxtaposed, each monomer binds ADP (PubMed:27821762, PubMed:27391173). At cell poles and septa interacts with methyl-accepting chemotaxis protein Amb0944 (MCP10) (PubMed:20471399). Forms filaments with MamK-like protein (PubMed:24957623). Tagged protein forms straight lines extending along most of the cell associated with its inner curvature, in the correct position to be filaments that are seen associated with magnetosomes (PubMed:17085581, PubMed:16373532, PubMed:20471399, PubMed:27481925, PubMed:21883528). Colocalizes in filaments with paralog MamK-like (PubMed:24957623). Constitutively expressed, levels remain the same over 144 hours of growth (at protein level) (PubMed:25048532). Expressed during exponential phase in static growth conditions (PubMed:20161777). Expressed during late exponential phase in the presence and absence of the mamK-like gene (PubMed:24957623). Part of the probable 18 gene mamAB operon (Probable). Domains close around the active site upon filament formation, which probably enhances nucleotide hydrolysis (PubMed:27821762). Nucleotide-binding also probably induces domain movement (Probable). Magnetosomes are dispersed in groups of 2-3 throughout the cytoplasm, no evidence of magnetosome-associated filaments. Cells form magnetite and turn in magnetic fields (PubMed:16373532, PubMed:26884433). Unanchored magnetosomes move randomly in the cytoplasm. Magnetosomes are unevenly segregated to daughter cells (PubMed:28790202). About 45% reduction in magnetosome alignment; a double mamK-mamK-like deletion has a 65% reduction in magnetosome alignment. MamK-like protein forms many fewer filaments (PubMed:24957623). Another paper shows deletion of mamK to yield approximately wild-type magnetosomes (PubMed:20161777). Deletion of genes mamH to mamV (amb0961 to amb0978) gives cells with no magnetosomes and no magnetic response (PubMed:20212111). This bacteria makes up to 20 cubo-octahedral magnetosomes of about 45 nm in diameter which contain membrane-bound crystals of magnetite (Fe(3)O(4)). Expression of just the minimal mamAB gene cluster (amb0961 to amb0978), including this gene, is sufficient to form a minimal magnetosome chain with small magnetite particles. In the related bacteria M.gryphiswaldense strain MSR-1 the magnetosome position moves from cell pole to mid cell during cytokinesis. Belongs to the FtsA/MreB family. MamK subfamily.