Part of the ecpRABCDE operon, which encodes the E.coli common pilus (ECP). ECP is found in both commensal and pathogenic strains and plays a dual role in early-stage biofilm development and host cell recognition. Positively regulates the expression of the ecp operon (By similarity). Also represses expression of the flagellar master operon flhDC, and consequently prevents flagellum biosynthesis and motility. Acts by binding to the regulatory region of the flhDC operon (Probable). Negatively regulated by H-NS. Positively autoregulated. Also positively regulated by IHF (By similarity). Expressed in strain K12. Belongs to the EcpR/MatA family.