May be involved in constriction of the cell inner membrane to form mature magnetosomes. Binds cardiolipin and liposomes (By similarity). May function with MamX, MamZ amd Mms6 in biomineralization (Probable). Probably interacts with MamX and MamZ proteins. Expressed in exponential phase, peaks about 18 hours (PubMed:20023033, PubMed:24020498). Protein is associated with magnetosomes as they start to develop, rises to a maximum quickly (at protein level) (PubMed:30367002). First gene in the 4 gene mamXY operon (PubMed:20023033) (Probable). Deletion of 4 consecutive genes (mamY, mamX, mamZ, ftsZm) leads to cells with an intermediate magnetic response where magnetosomes have short chains of nearly regularly shaped, cubo-octahedral crystals flanked by small particles with poorly defined morphologies. This bacteria makes up to 60 cubo-octahedral magnetosomes of about 45 nm in diameter which contain membrane-bound crystals of magnetite (Fe(3)O(4)). Belongs to the magnetosome MamY family.