Regulates cell growth and peptidoglycan synthesis by binding to MviN. May inhibit the late stages of peptidoglycan synthesis. Interacts with (phosphorylated) MviN and (phosphorylated) PknB via the FHA domain. Binds to the PknB juxtamembrane domain with an affinity that is modulated by the degree and the pattern of phosphorylation of this juxtamembrane domain. Localizes at the cell poles and at the septum. The structure of the N-terminal domain remains unchanged upon phosphorylation. Phosphorylated by PknB.