ARABIDOPSIS-THALIANA CDNA-ENCODING A NOVEL MEMBER OF THE EF-HAND SUPERFAMILY OF CALCIUM-BINDING PROTEINS
ARABIDOPSIS-THALIANA CDNA-ENCODING A NOVEL MEMBER OF THE EF-HAND SUPERFAMILY OF CALCIUM-BINDING PROTEINS
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DOI：
10.1104/pp.102.3.1059
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发表时间：
1993-07-01
期刊：
影响因子：
7.4
通讯作者：
WEILER, EW
中科院分区：
文献类型：
--
作者：
BARTLING, D;BULTER, H;WEILER, EW
由于其结构和调节功能，钙在任何活细胞中都起着至关重要的作用。在植物细胞中，钙作为第二信使，可以从内部储存中释放（McAinsh et al., 1990; Knight et al., 1992; Roberts and Harmon, 1992）或从外质体进入细胞，以响应各种刺激，如病原体攻击时的激发（Stab and Ebel, 1989）、植物激素ABA （McAinsh et al., 1990）或机械应力（Knight et al., 1992）。细胞内钙信号是如何调节植物细胞功能的，这在很大程度上仍然是未知的，但很明显，钙作用的直接目标是钙调节蛋白（回顾，见Roberts和Harmon， 1992）。一个拟南芥cDNA文库的成员过度表达质膜相关蛋白（Bartling et al., 1992）被发现编码一种新的efhand蛋白，明显不同于常见的钙调素。南方分析表明，拟南芥中只有一个基因位点（表1）。该892 bp cDNA （PM129）包含一个连续开放阅读框，对应215个氨基酸的蛋白，预测分子量为23278 D.该蛋白序列与拟水藻（Perera and Zielinski, 1992）、小麦（Toda et al., 1985）和菠菜（Lukas et al., 1984）的钙调素氨基酸同源性分别为34.8%和34.0%。因此，PM129编码的蛋白显然与钙调蛋白家族相关，但肯定不是钙调蛋白家族的成员，钙调蛋白家族在植物中甚至在动植物之间都是高度保守的。推断出的PMl29的氨基酸序列显示了四个典型的螺旋-转-螺旋结构域，或EF-hands (Nakayama et al., 1992)，其中包含了功能钙结合位点所需的11种元素。PM129是一类新的EF-hand蛋白的成员，在动物王国中没有已知的对应物。
Calcium plays a vital role in any living cell because of its structural as well as regulatory functions. In the plant cell, calcium acts as a second messenger and may be released from interna1 stores (McAinsh et al., 1990; Knight et al., 1992; Roberts and Harmon, 1992) or enter the cell from the apoplast (Schroeder and Hagiwara, 1989) in response to various stimuli, such as elicitation during pathogen attack (Stab and Ebel, 1989), the phytohormone ABA (McAinsh et al., 1990), or mechanical stress (Knight et al., 1992). How the intracellular calcium signal serves to regulate plant cell function is still largely unknown, but it is clear that immediate targets of calcium action are calcium-modulated proteins (for a review, see Roberts and Harmon, 1992). A member of an Arabidopsis thaliana cDNA library that overrepresents plasma membrane-associated proteins (Bartling et al., 1992) was found to encode a novel EF-hand protein clearly different from the common calmodulins. Southem analysis of the cDNA indicates a single gene locus in A. thaliana (Table I). The 892-bp cDNA (PM129) contains one continuous open reading frame corresponding to a protein of 215 amino acids with a predicted molecular mass of 23,278 D. The protein sequence shares 34.8% and 34.0% amino acid identity with calmodulins from A. thaliana (Perera and Zielinski, 1992), wheat (Toda et al., 1985), and spinach (Lukas et al., 1984). The protein encoded by PM129 is thus clearly related to, but certainly not a member of, the calmodulin family, which is highly conserved among plants and even between plants and animals. The deduced amino acid sequence of PMl29 displays four typical helix-tum-helix domains, or EF-hands (Nakayama et al., 1992), which contain a11 of the elements required for functional calcium-binding sites. PM129 is a member of a novel class of EF-hand proteins having no known counterpart in the animal kingdom.