Plays an important role in bacterial chemotaxis signal transduction pathway by accelerating the dephosphorylation of phosphorylated CheY (CheY-P). Homodimer. Interacts with CheA isoform CheA(short). Interacts (via C-terminus) with phosphorylated CheY (CheY-P). Colocalizes with CheA chemoreceptor patches near the cell poles, which requires CheA(short). Belongs to the CheZ family.