Probable aspartic protease that is responsible for the proteolytic cleavage of the RNA polymerase sigma E factor (SigE/spoIIGB) to yield the active peptide in the mother cell during sporulation. Responds to a signal from the forespore that is triggered by the extracellular signal protein SpoIIR (By similarity). Self-associates. Interacts with SigE. Interacts with SpoIIR (By similarity). Localized to the sporulation septum. Early in sporulating cells localized in an annulus at the septal periphery and later localized uniformly throughout the septa. Belongs to the peptidase U4 family. Truncated N-terminus.