Visconti Sabina, Camoni Lorenzo, Marra Mauro, Aducci Patrizia
Department of Biology, University of Rome Tor Vergata, via della Ricerca Scientifica, 00133, Rome, Italy.
Plant Cell Physiol. 2008 Dec;49(12):1887-97. doi: 10.1093/pcp/pcn172. Epub 2008 Nov 10.
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 H(+)-ATPase. Results obtained demonstrate that removal of the last 22 amino acids residues of GF14-6 increases binding to H(+)-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 H(+)-ATPase and to stimulate the enzyme activity. The implications of these findings for a integrated model of 14-3-3 interaction with H(+)-ATPase are discussed.
14-3-3蛋白是一类存在于所有真核生物中多种亚型的蛋白质，参与许多细胞功能的调控。通过一种保守机制与磷酸化靶点结合来实现对不同活性的调节。尽管在许多系统中已证明亚型特异性，但潜在的分子基础仍不清楚。14-3-3亚型的序列高度保守，差异发生在N端和C端区域。最近有人提出，14-3-3的C端结构域可能调节蛋白质与靶点的结合。在此，我们研究玉米亚型GF14-6的C端区域在与植物质膜H(+) -ATP酶相互作用中的作用。获得的结果表明，去除GF14-6的最后22个氨基酸残基会增加与H(+) -ATP酶的结合并刺激其活性。此外，C端缺失会降低14-3-3对阳离子的敏感性。我们还表明，一个复制GF14-6 C端的肽能够与H(+) -ATP酶的C端结构域结合并刺激酶活性。讨论了这些发现对14-3-3与H(+) -ATP酶相互作用的整合模型的意义。
