Essential cell division protein that forms a contractile ring structure (Z ring) at the future cell division site. The regulation of the ring assembly controls the timing and the location of cell division. One of the functions of the FtsZ ring is to recruit other cell division proteins to the septum to produce a new cell wall between the dividing cells. Binds GTP and shows GTPase activity (By similarity). Mild overexpression impairs cell division, leading to very elongated cells. Isolated protein forms filaments and bundles in the presence of GTP (PubMed:24272781). Homodimer. Polymerizes to form a dynamic ring structure in a strictly GTP-dependent manner. Interacts directly with several other division proteins (By similarity). Interacts with FtsZ-like protein (also called FtsZm) (Probable). Assembles at midcell at the inner surface of the cytoplasmic membrane (Probable). Upon mild overexpression during extended growth additional foci appear, which are probably blocked division sites. Foci colocalize with FtsZ-like protein (also called FtsZm) (PubMed:24272781). Essential; it cannot be disrupted. Although it colocalizes with paralog FtsZ-like, the latter cannot replace it. Belongs to the FtsZ family.