PLANT AND MAMMALIAN SORTING SIGNALS FOR PROTEIN RETENTION IN THE ENDOPLASMIC-RETICULUM CONTAIN A CONSERVED EPITOPE
PLANT AND MAMMALIAN SORTING SIGNALS FOR PROTEIN RETENTION IN THE ENDOPLASMIC-RETICULUM CONTAIN A CONSERVED EPITOPE
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DOI：
10.1002/j.1460-2075.1992.tb05294.x
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发表时间：
1992-06-01
期刊：
影响因子：
11.4
通讯作者：
BOTTERMAN, J
中科院分区：
文献类型：
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作者：
DENECKE, J;DERYCKE, R;BOTTERMAN, J
我们研究了负责在植物内质网（ER）的管腔中保留网状蛋白质的蛋白质分选信号。一种非特异性的乘客蛋白，以前被证明是默认分泌，被用作这种信号的载体。用哺乳动物（KDEL）和酵母（HDEL）网状浆蛋白的C-末端四肽序列标记导致蛋白质嵌合体在植物ER的内腔中有效积累。四肽标签内的一些单个氨基酸取代（-SDEL、-KDEI、-KDEI和-KDEV）可导致其作为保留信号的功能完全丧失，证明保留机制的高特异性。然而，其他修饰赋予有效（-RDEL）或部分（-KEEL）保留。它还表明，蛋白质保留的效率并没有显着受损的植物中的配体浓度增加。有效保留的嵌合体（-KDEL，-HDEL和-RDEL）被证明是由针对哺乳动物网状血浆蛋白二硫键异构酶（PDI）的C-末端的单克隆抗体识别。所识别的表位也存在于植物和哺乳动物细胞的微粒体组分中的几种推定的网状纤溶酶中，这表明抗体识别保留信号的重要结构决定因素。此外，数据进行了讨论，支持的观点，上游序列超出了C-末端四肽可以影响或可能是网状蛋白保留信号的结构的一部分。
We studied protein sorting signals which are responsible for the retention of reticuloplasmins in the lumen of the plant endoplasmic reticulum (ER). A non-specific passenger protein, previously shown to be secreted by default, was used as a carrier for such signals. Tagging with C-terminal tetrapeptide sequences of mammalian (KDEL) and yeast (HDEL) reticuloplasmins led to effective accumulation of the protein chimeras in the lumen of the plant ER. Some single amino acid substitutions within the tetrapeptide tag (-SDEL, -KDDL, -KDEI and -KDEV) can cause a complete loss of its function as a retention signal, demonstrating the high specificity of the retention machinery. However, other modifications confer efficient (-RDEL) or partial (-KEEL) retention. It is also shown that the efficiency of protein retention is not significantly impaired by an increased ligand concentration in plants. The efficiently retained chimeras (-KDEL, -HDEL and -RDEL) were shown to be recognized by a monoclonal antibody directed against the C-terminus of the mammalian reticuloplasmin protein disulfide isomerase (PDI). The recognized epitope is also present in several putative reticuloplasmins in microsomal fractions of plant and mammalian cells, suggesting that the antibodies recognize an important structural determinant of the retention signal. In addition, data are discussed which support the view that upstream sequences beyond the C-terminal tetrapeptide can influence or may be part of the structure of reticuloplasmin retention signals.