Involved in regulation of glutamate metabolism. Acts as a phosphorylation-dependent molecular switch that modulates the activities of Kgd and Gdh. Monomer (By similarity). Binds via its FHA domain to Kgd, Gdh, and the N-terminal region of PknG. Phosphorylated on Thr-21 by PknB (By similarity). Phosphorylated on Thr-20 by PknG. Phosphorylation at either Thr-20 or Thr-21 prevents binding to target enzymes. Truncated N-terminus.