Letourneur F, Cosson P
Institut de Biologie et de Chimie des Protéines, 69367 Lyon, France.
J Biol Chem. 1998 Dec 11;273(50):33273-8. doi: 10.1074/jbc.273.50.33273.
The transmembrane domains (TMDs) of many type I integral membrane proteins contain determinants that cause localization in the endoplasmic reticulum (ER) in mammalian cells by an unknown mechanism. Here we show that the yeast ER localization machinery recognizes determinants in TMDs that are very similar to those identified previously in mammalian cells. These determinants are recognized in post-ER compartments and recycled back to the ER, thus acting as ER retrieval signals. Moreover determinants in TMDs are inefficiently sorted in several previously characterized yeast mutants with defects in the ER retrieval machinery. Similar ER retrieval signals are also recognized in the TMDs of polytopic integral membrane proteins, apparently by the same sorting machinery. The isolation of new mutants defective in sorting of membrane determinants might provide a better understanding of the molecular mechanisms involved in this process.
许多I型整合膜蛋白的跨膜结构域（TMDs）含有一些决定因素，它们通过一种未知机制导致在哺乳动物细胞的内质网（ER）中定位。在这里，我们表明酵母内质网定位机制识别TMDs中的决定因素，这些决定因素与先前在哺乳动物细胞中鉴定出的决定因素非常相似。这些决定因素在ER后区室中被识别并循环回到ER，因此作为ER回收信号起作用。此外，TMDs中的决定因素在几种先前表征的具有ER回收机制缺陷的酵母突变体中分类效率低下。多聚体整合膜蛋白的TMDs中也明显通过相同的分类机制识别类似的ER回收信号。分离在膜决定因素分类方面有缺陷的新突变体可能有助于更好地理解这一过程中涉及的分子机制。
