Wang W, Shakes D C
Department of Biology, University of Houston, Houston, TX 77204-5513, USA.
J Mol Evol. 1996 Oct;43(4):384-98. doi: 10.1007/BF02339012.
Members of the highly conserved and ubiquitous 14-3-3 protein family modulate a wide variety of cellular processes. To determine the evolutionary relationships among specific 14-3-3 proteins in different plant, animal, and fungal species and to initiate a predictive analysis of isoform-specific differences in light of the latest functional and structural studies of 14-3-3, multiple alignments were constructed from forty-six 14-3-3 sequences retrieved from the GenBank and SwissProt databases and a newly identified second 14-3-3 gene from Caenorhabditis elegans. The alignment revealed five highly conserved sequence blocks. Blocks 2-5 correlate well with the alpha helices 3, 5, 7, and 9 which form the proposed internal binding domain in the three-dimensional structure model of the functioning dimer. Amino acid differences within the functional and structural domains of plant and animal 14-3-3 proteins were identified which may account for functional diversity amongst isoforms. Protein phylogenic trees were constructed using both the maximum parsimony and neighbor joining methods of the PHYLIP(3.5c) package; 14-3-3 proteins from Entamoeba histolytica, an amitochondrial protozoa, were employed as an outgroup in our analysis. Epsilon isoforms from the animal lineage form a distinct grouping in both trees, which suggests an early divergence from the other animal isoforms. Epsilons were found to be more similar to yeast and plant isoforms than other animal isoforms at numerous amino acid positions, and thus epsilon may have retained functional characteristics of the ancestral protein. The known invertebrate proteins group with the nonepsilon mammalian isoforms. Most of the current 14-3-3 isoform diversity probably arose through independent duplication events after the divergence of the major eukaryotic kingdoms. Divergence of the seven mammalian isoforms beta, zeta, gamma, eta, epsilon, tau, and sigma (stratifin/HME1) occurred before the divergence of mammalian and perhaps before the divergence of vertebrate species. A possible ancestral 14-3-3 sequence is proposed.
高度保守且广泛存在的14-3-3蛋白家族成员可调节多种细胞过程。为了确定不同植物、动物和真菌物种中特定14-3-3蛋白之间的进化关系，并根据14-3-3最新的功能和结构研究对异构体特异性差异进行预测分析，我们从GenBank和SwissProt数据库中检索到的46个14-3-3序列以及从秀丽隐杆线虫中新鉴定出的第二个14-3-3基因构建了多重比对。比对结果显示有五个高度保守的序列块。序列块2至5与α螺旋3、5、7和9高度相关，这些螺旋在功能性二聚体的三维结构模型中形成了拟内部结合域。我们鉴定出了植物和动物14-3-3蛋白功能和结构域内的氨基酸差异，这些差异可能解释了异构体之间的功能多样性。使用PHYLIP(3.5c)软件包的最大简约法和邻接法构建了蛋白质系统发育树；来自无线粒体原生动物溶组织内阿米巴的14-3-3蛋白被用作我们分析中的外类群。动物谱系中的ε异构体在两棵树中都形成了一个独特的分组，这表明它与其他动物异构体的分化较早。在许多氨基酸位置上，发现ε异构体与酵母和植物异构体比与其他动物异构体更相似，因此ε可能保留了祖先蛋白的功能特征。已知的无脊椎动物蛋白与非ε哺乳动物异构体归为一类。目前大多数14-3-3异构体的多样性可能是在主要真核生物界分化后通过独立的复制事件产生的。七种哺乳动物异构体β、ζ、γ、η、ε、τ和σ（stratifin/HME1）的分化发生在哺乳动物分化之前，甚至可能在脊椎动物物种分化之前。我们提出了一个可能的14-3-3祖先序列。
