Role of the 14-3-3 C-terminal region in the interaction with the plasma membrane H+ -ATPase
2008
Visconti, S.(University of Rome (Italy)) | Camoni, L. | Marra, M. | Aducci, P.
The 14-3-3 proteins are a family of proteins present in a number of isoforms in all eukaryotes and involved in the control of many cellular functions. Regulation of different activities is achieved by binding to phosphorylated targets through a conserved mechanism. Although in many systems isoform specificity has been demonstrated, the underlying molecular basis is still unclear. The sequences of 14-3-3 isoforms are highly conserved, divergence occurring at the N- and C-terminal regions. Recently it has been suggested that the C-terminal domain of 14-3-3 may regulate protein binding to the targets. Here we study the role of the C-terminal region of maize isoform GF14-6 in the interaction with the plant plasma membrane Hsup(+)-ATPase. Results obtained demonstrate that removal of the last 22 amino acids residues of GF14-6 increases binding to Hsup(+)-ATPase and stimulation of its activity. C-terminal deletion, moreover, reduces 14-3-3 sensitivity to cations. We also show that a peptide reproducing the GF14-6 C-terminus is able to bind to the C-terminal domain of Hsup(+)-ATPase and to stimulate the enzyme activity. The implications of these findings for a integrated model of 14-3-3 interaction with Hsup(+)-ATPase are discussed.
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