Deepti Singh, Priyanka Gupta, Sneh Lata Singla-Pareek, Kadambot H.M. Siddique and Ashwani Pareek* Pages 59 - 74 ( 16 )
Background: The two-component signaling (TCS) system is an important signal transduction machinery in prokaryotes and eukaryotes, excluding animals, that uses a protein phosphorylation mechanism for signal transmission.
Conclusion: Prokaryotes have a primitive type of TCS machinery, which mainly comprises a membrane- bound sensory histidine kinase (HK) and its cognate cytoplasmic response regulator (RR). Hence, it is sometimes referred to as two-step phosphorelay (TSP). Eukaryotes have more sophisticated signaling machinery, with an extra component - a histidine-containing phosphotransfer (HPT) protein that shuttles between HK and RR to communicate signal baggage. As a result, the TSP has evolved from a two-step phosphorelay (His–Asp) in simple prokaryotes to a multi-step phosphorelay (MSP) cascade (His–Asp–His–Asp) in complex eukaryotic organisms, such as plants, to mediate the signaling network. This molecular evolution is also reflected in the form of considerable structural modifications in the domain architecture of the individual components of the TCS system. In this review, we present TCS system's evolutionary journey from the primitive TSP to advanced MSP type across the genera. This information will be highly useful in designing the future strategies of crop improvement based on the individual members of the TCS machinery.
Two-component system, histidine kinases, histidine-containing phosphotransfer proteins, response regulators, multi-step phosphorelay, two-step phosphorelay.
Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, The UWA Institute of Agriculture, The University of Western Australia, Perth WA 6001, Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067