A protein complex required for prokaryotic cell division (FtsZ-dependent cytokinesis). These complexes are assembled and recruited to the cell septum in a strictly controlled sequence and co-ordinate invagination of the cell membrane, inward growth of the peptidoglycan layer, constriction of the outer membrane and separation of daughter cells. [ http://www.ncbi.nlm.nih.gov/pubmed/15165235 http://www.ncbi.nlm.nih.gov/pubmed/21784946 ]