Lee H I, Gal S, Newman T C, Raikhel N V
Michigan State University-Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing 48824-1312.
Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):11433-7. doi: 10.1073/pnas.90.23.11433.
Soluble proteins retained in the lumen of the endoplasmic reticulum (ER) contain a carboxyl-terminal tetrapeptide sequence that functions presumably to recycle these proteins from a subsequent compartment. Biochemical and genetic evidence indicate that the ERD2 gene product is the receptor for these ER retention signals. Here we report the identification of a cDNA clone from Arabidopsis thaliana (aERD2) similar in sequence and size to members of the ERD2 gene family. Southern and Northern blot analyses indicate that Arabidopsis contains a single aERD2 gene which is expressed at different levels in various plant tissues. A functional assay demonstrates that the Arabidopsis homologue, unlike the mammalian protein, can complement the lethal phenotype of the erd2 deletion mutant of Saccharomyces cerevisiae, indicating that this protein may have a similar function in plants. As the plant protein may have a binding specificity similar to the human Erd2 protein but can function in yeast, we suggest that the plant homologue is the functional link between yeast and animals.
保留在内质网（ER）腔中的可溶性蛋白质含有一个羧基末端四肽序列，其作用可能是将这些蛋白质从后续区室中循环利用。生化和遗传学证据表明，ERD2基因产物是这些ER保留信号的受体。在此，我们报告了从拟南芥中鉴定出一个cDNA克隆（aERD2），其序列和大小与ERD2基因家族成员相似。Southern和Northern印迹分析表明，拟南芥含有单个aERD2基因，该基因在各种植物组织中以不同水平表达。功能分析表明，与哺乳动物蛋白不同，拟南芥同源物可以互补酿酒酵母erd2缺失突变体的致死表型，表明该蛋白在植物中可能具有类似功能。由于植物蛋白可能具有与人类Erd2蛋白相似的结合特异性，但可以在酵母中发挥作用，我们认为植物同源物是酵母和动物之间的功能联系。
