To access the full text documents, please follow this link: http://hdl.handle.net/10459.1/45588

Two component systems: physiological effect of a third component
Salvado, Baldiri; Vilaprinyo Terré, Ester; Karathia, Hiren; Sorribas Tello, Albert; Alves, Rui
Signal transduction systems mediate the response and adaptation of organisms to environmental changes. In prokaryotes, this signal transduction is often done through Two Component Systems (TCS). These TCS are phosphotransfer protein cascades, and in their prototypical form they are composed by a kinase that senses the environmental signals (SK) and by a response regulator (RR) that regulates the cellular response. This basic motif can be modified by the addition of a third protein that interacts either with the SK or the RR in a way that could change the dynamic response of the TCS module. In this work we aim at understanding the effect of such an additional protein (which we call ‘‘third component’’) on the functional properties of a prototypical TCS. To do so we build mathematical models of TCS with alternative designs for their interaction with that third component. These mathematical models are analyzed in order to identify the differences in dynamic behavior inherent to each design, with respect to functionally relevant properties such as sensitivity to changes in either the parameter values or the molecular concentrations, temporal responsiveness, possibility of multiple steady states, or stochastic fluctuations in the system. The differences are then correlated to the physiological requirements that impinge on the functioning of the TCS. This analysis sheds light on both, the dynamic behavior of synthetically designed TCS, and the conditions under which natural selection might favor each of the designs. We find that a third component that modulates SK activity increases the parameter space where a bistable response of the TCS module to signals is possible, if SK is monofunctional, but decreases it when the SK is bifunctional. The presence of a third component that modulates RR activity decreases the parameter space where a bistable response of the TCS module to signals is possible.
2012
Transducció de senyal cel·lular
Proteïnes
http://creativecommons.org/licenses/by/2.5/es/deed.ca
cc-by, (c) Salvado et al., 2012
article
Public Library of Science
         

Full text files in this document

Files Size Format View
journal.pone.0031095.pdf 2.177 MB application/pdf View/Open

Full text files in this document

Files Size Format View

Show full item record

Related documents

Other documents of the same author

 

Coordination

 

Supporters