RICERCA ITALIANA     

Regulatory proteins in plants. Bio-molecular analysis of the interaction of 14-3-3 proteins and calmodulin with target proteins

Università degli Studi di Roma "Tor Vergata"

Abstract

The role of protein-protein interaction in different plant cellular processes is the aim of the present project. Among known signal molecules, calmodulin (CaM) and 14-3-3 proteins play a specific role in different signal transduction pathways. Molecular mechanisms for their action have been elucidated only in the last years.
Both CaM and 14-3-3 proteins are highly conserved, and play a regulatory role through their specific interaction with target proteins and enzymes.
14-3-3 proteins and CaM have been chosen in this project where the regulation at molecular level of their interaction with some specific targets will be studied, in particular type IIB Ca-ATPase for CaM- and H+-ATPase and a MAPK for 14-3-3 proteins.
The experimental plan is designed around the study of the kinetic, biochemical and molecular parameters of the interactions between the two signal proteins and their targets and the physiological role played by these interactions.
Moreover, it will be studied in tight collaboration between the two groups:1) molecular mechanism of regulation of different P-type ATPases, targets of the two signal 14-3-3 proteins and CaM. in order to identify a possible common autoinhibitory mechanism, 2) possible interaction and functional relationship between the two signal proteins in plants, as already suggested in mammals. The collaboration between the two proponents groups, both with a ascertained experience in the field is already established >>>

Principal Investigator

Patrizia ADUCCI Università degli Studi di ROMA "Tor Vergata"

Research Objectives

The study of the role of protein-protein interaction in different plant cellular processes is a matter of primary importance for the comprehension of mechanisms regulating plant responses to various endogenous and environmental stimuli. Only in the last years these mechanisms have been elucidated at molecular level and it appears that signal molecules, such as calmodulin (CaM) and 14-3-3 proteins play a specific role in different signal transduction pathways. Moreover, these proteins are highly conserved in animal systems, where they play a regulatory role through their specific interaction with target proteins and enzymes, some of them conserved both in animal and plant systems. Both CaM and 14-3-3 proteins are present in different isoforms, depending on the species; a different physiological role and target interaction has been attributed to each isoform.
The aim of this program is the elucidation at the bio-molecular level of the interaction mechanism of CaM and 14-3-3 proteins with their targets, particularly type IIB Ca-ATPase for CaM- and H+-ATPase and a MAPK for 14-3-3 proteins. Moreover, in this project we intend to verify whether CaM and 14-3-3 proteins can interact, as suggested in mammals.
The kinetic, biochemical and molecular parameters of these interactions and their role in the physiological regulation will be considered.
Both proponent groups have a well-established experience in the field and a prolonged profitable collaboration >>>

Timescale

24 months

National and international background

This proposal studies two families of regulatory proteins that are evolutionary conserved across all eukaryotes and involved in protein-protein interactions that mediate cell type and development specific signal transduction pathways.While they are clearly evolutionary conserved, most eukaryotes, including planta have range of genes and proteins often divergent and leading to specialised structures and functions. Among the wide range of regulatory proteins known so far, calmodulin (CaM) and 14-3-3 proteins have been extensively investigated in plants, because of their specialised and diverse role in a number of processes, including development, growth and responses to endogenous signals and biotic and abiotic stresses. Both CaM and 14-3-3 proteins have no catalytic activity of their own. Their regulatory activities are manifested by their ability to modulate a set of enzymes and non enzymatic proteins.
Thus, it is crucial to characterize the interaction with isolated target proteins to understand the role of CaM- and 14-3-3-mediated networks.

14-3-3 proteins:
14-3-3 proteins are a family of proteins widely distributed and highly conserved in a variety of organisms including yeast, mammals and plants (Ferl, 1996, Fu et al., 2000, Roberts, 2000). They exist as a number of isoforms (Wang and Shakes, 1996) that can form homo and heterodimers in vivo (Jones et al., 1995).
14-3-3 proteins play an important role in the regulation of several >>>