Molecular evolution of integrins: Genes encoding integrin beta subunits from a coral and a sponge
Molecular evolution of integrins: Genes encoding integrin beta subunits from a coral and a sponge
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DOI：
10.1073/pnas.94.17.9182
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发表时间：
1997-08-19
影响因子：
11.1
通讯作者：
Ball, EE
中科院分区：
文献类型：
--
作者：
Brower, DL;Brower, SM;Ball, EE
整合素家族是一个高度保守的细胞表面受体家族，但其进化历史尚不清楚。（刺胞动物门）和海绵（多孔动物），表明这些蛋白质存在于后生动物进化的最早阶段，珊瑚β（Cn 1），特别是，海绵β（Po1）序列是“β（1）类”整联蛋白中最趋异的，并且具有许多在任何其它脊椎动物或无脊椎动物整联蛋白中未发现的特征。与其它β亚基的最大差异可能存在于富含半胱氨酸的茎的第三和第四重复序列中，其中半胱氨酸之间通常保守的间距在β（Cn 1）和β（Po 1）中高度可变，但不相似。从海绵文库中分离出可变剪接的cDNA，其在全长翻译序列的大约中间含有终止密码子。这些cDNA似乎定义了功能结构域之间的边界，因为它们将编码包括球状配体结合头部但将缺失茎跨膜和胞质结构域的蛋白质。这些和其他序列与脊椎动物整合素的比较进行了讨论整合素的结构和功能的模型。
The integrin family of cell surface receptors is strongly conserved in higher animals, but the evolutionary history of integrins is obscure, We have identified and sequenced cDNAs encoding integrin beta subunits from a coral (phylum Cnidaria) and a sponge (Porifera), indicating that these proteins existed in the earliest stages of metazoan evolution, The coral beta(Cn1) and, especially, the sponge beta(Po1) sequences are the most divergent of the ''beta(1)-class'' integrins and share a number of features not found in any other vertebrate or invertebrate integrins, Perhaps the greatest difference from other beta subunits is found in the third and fourth repeats of the cysteine-rich stalk, where the generally conserved spacings between cysteines are highly variable, but not similar, in beta(Cn1) and beta(Po1). Alternatively spliced cDNAs, containing a stop codon about midway through the full-length translated sequence, were isolated from the sponge library, These cDNAs appear to define a boundary between functional domains, as they would encode a protein that includes the globular ligand-binding head but would be missing the stalk transmembrane, and cytoplasmic domains. These and other sequence comparisons with vertebrate integrins are discussed with respect to models of integrin structure and function.