This P-loop motif-containing family of proteins includes AFG1, LACE1 and ZapE. ATPase family gene 1 (AFG1) is a 377 amino acid yeast protein with an ATPase motif typical of the family. LACE1, the mammalian homolog of AFG1, is a mitochondrial integral membrane protein that is essential for maintenance of fused mitochondrial reticulum and lamellar cristae morphology. It has also been demonstrated that LACE1 mediates degradation of nuclear-encoded complex IV subunits COX4 (cytochrome c oxidase 4), COX5A and COX6A, and is required for normal activity of complexes III and IV of the respiratory chain. ZapE is a cell division protein found in Gram-negative bacteria. The bacterial cell division process relies on the assembly, positioning, and constriction of FtsZ ring (the so-called Z-ring), a ring-like network that marks the future site of the septum of bacterial cell division. ZapE is a Z-ring associated protein required for cell division under low-oxygen conditions. It is an ATPase that appears at the constricting Z-ring late in cell division. It reduces the stability of FtsZ polymers in the presence of ATP in vitro.