Protein histidine kinases and signal transduction in prokaryotes and eukaryotes.

During the past several years, it has become apparent that prokaryotic organisms process much of their sensory information through families of similar proteins that make up two-component signal transducing systems. Biochemical and genetic analyses have clarified our understanding of how these proteins mediate the signaling circuitry necessary to allow an appropriate response. Recent advances in this field suggest that 'primitive' signaling systems may involve molecular strategies and mechanisms that are conserved in more complex organisms.