Department of Environmental Science and Technology, Saitama University, Saitama 338-8570, Japan.
Cell Death Differ. 2011 Aug;18(8):1271-8. doi: 10.1038/cdd.2011.59. Epub 2011 May 20.
In spite of fundamental differences between plant and animal cells, it is remarkable that some cell death regulators that were identified to control cell death in metazoans can also function in plants. The fact that most of these proteins do not have structural homologs in plant genomes suggests that they may be targeting a highly conserved 'core' mechanism with conserved functions that is present in all eukaryotes. The ubiquitous Bax inhibitor-1 (BI-1) is a common cell death suppressor in eukaryotes that has provided a potential portal to this cell death core. In this review, we will update the current status of our understanding on the function and activities of this intriguing protein. Genetic, molecular and biochemical studies have so far suggested a consistent view that BI-1 is an endoplasmic reticulum (ER)-resident transmembrane protein that can interact with multiple partners to alter intracellular Ca(2+) flux control and lipid dynamics. Functionally, the level of BI-1 protein has been hypothesized to have the role of a rheostat to regulate the threshold of ER-stress inducible cell death. Further, delineation of the cell death suppression mechanism by BI-1 should shed light on an ancient cell death core-control pathway in eukaryotes, as well as novel ways to improve stress tolerance.
尽管植物细胞和动物细胞之间存在根本差异，但令人惊讶的是，一些被鉴定为控制后生动物细胞死亡的细胞死亡调节剂也可以在植物中发挥作用。这些蛋白质大多数在植物基因组中没有结构同源物这一事实表明，它们可能针对的是一种高度保守的“核心”机制，这种机制具有在所有真核生物中都保守的功能。普遍存在的 Bax 抑制剂-1（BI-1）是真核生物中常见的细胞死亡抑制剂，它为研究细胞死亡核心提供了一个潜在的途径。在这篇综述中，我们将更新对该引人入胜的蛋白质的功能和活性的现有认识。遗传、分子和生化研究迄今为止表明了一个一致的观点，即 BI-1 是一种内质网（ER）驻留的跨膜蛋白，它可以与多个伴侣相互作用，改变细胞内 Ca(2+) 流的控制和脂质动力学。从功能上讲，BI-1 蛋白的水平被假设为具有调节 ER 应激诱导细胞死亡的阈值的变阻器的作用。此外，BI-1 抑制细胞死亡的机制的描绘应该阐明真核生物中古老的细胞死亡核心控制途径，以及提高应激耐受性的新方法。
