Part of the ABC transporter FtsEX involved in cellular division. Important for assembly or stability of the septal ring. Encoded in an operon consisting of genes ftsY, ftsE and ftsX. Forms a membrane-associated complex with FtsE. Localizes to the septal ring at the later stages of cell growth and remains there until division is complete. This localization is dependent on localization of FtsZ, FtsA and ZipA, but not on the downstream division proteins FtsK, FtsQ or FtsI. Double deletion mutant FtsEX grows well on plates with LB medium with 1% NaCl forming healthy colonies at 30 degrees Celsius, whereas at 37 or 42 degrees Celsius, the colonies are very tiny and sick. In culture medium it exhibits mild elongation of cells at 30 degrees Celsius, and become very extensive at higher temperatures. This double mutant does not grow on LB culture medium without NaCl (LBON) at any temperature, possibly due to excessive lethal filamentation. Supplementation with any of a variety of osmolytes, such as glucose, sucrose, glycerol, or NaCl, completely rescues the growth on LBON medium. Though the growth is completely inhibited on LBON plates, the cultures grown in LBON broth show an initial increase in cell mass before the cessation of growth, and at this stage, the culture is extremely filamentous. The filaments grown in LB at 42 degrees Celsius or in LBON at 30 degrees Celsius are very long and appear to have elongated cells. They are normal and regularly spaced without any significant chromosomal aberrations or partition defects. Overexpression leads to strong inhibition of growth, cell filamentation and eventually cell death. Belongs to the ABC-4 integral membrane protein family. FtsX subfamily.