Global transcriptional regulator that regulates virulence factors production by activating or repressing the expression of a large set of genes in diffusible signal factor (DSF) pathway. It includes, among others, genes involved in extracellular polysaccharide (EPS) synthesis, flagellum synthesis, protein and fatty acid metabolism, multidrug resistance, iron uptake or genes encoding extracellular enzymes, membrane components and a few transcription factors. Regulation can be direct or indirect, via regulation of other transcriptional regulators. Not involved in DSF-mediated biofilm dispersal. Allosterically inhibited by cyclic di-GMP (c-di-GMP), which binds to Clp and abolishes its ability to bind its target gene promoter. Homodimer. Expression is induced by DSF signal, via the RpfC/RpfG two-component system. Binding of c-di-GMP appears to trigger the active Clp conformation into an open form or inactive state, hence abolishing its DNA-binding ability. Mutant produces less EPS and shows decrease in cellulase and protease activities.