Cell division protein that may be involved in stabilizing or promoting the assembly of the division complex. Localizes to the division septum. The extracellular region contains three distinct subdomains: a membrane proximal alpha domain, a central beta domain and a C-terminal gamma domain. The alpha domain might serve as a chaperone that stabilizes FtsL. The gamma domain is required for interaction with other divisomal proteins. The beta domain might modulate protein-protein interactions of the flanking alpha and gamma domains. Belongs to the FtsQ/DivIB family. DivIB subfamily.