Brunke M, Tyedmers J, Zimmermann R
Universität des Saarlandes, Homburg, Germany.
Biochem Biophys Res Commun. 1996 Jan 17;218(2):454-60. doi: 10.1006/bbrc.1996.0081.
Transport of presecretory proteins into mammalian microsomes involves a microsomal protein which is sensitive to photoaffinity labeling with 8-azido-ATP. Typically, protein folding within the lumen of the endoplasmic reticulum of mammalian cells depends on ATP and the member of the Hsp70 protein family, BiP. Here we addressed the question of whether protein transport into and folding within microsomes are differentially affected by photoaffinity labeling of microsomes with 8-azido-ATP. Folding of heterodimeric luciferase to the native state was more azido-ATP-sensitive compared to transport of the precursors of the two subunits. Therefore, we conclude that the microsomal protein which is responsible for the ATP-dependence of protein folding in the endoplasmic reticulum is sensitive to photoaffinity labeling with 8-azido-ATP and that this microsomal protein is distinct from the microsomal ATP-binding protein which is involved in protein transport.
分泌前体蛋白转运到哺乳动物微粒体的过程涉及一种对8-叠氮基-ATP光亲和标记敏感的微粒体蛋白。通常，哺乳动物细胞内质网腔中的蛋白质折叠依赖于ATP和Hsp70蛋白家族成员BiP。在此，我们探讨了用8-叠氮基-ATP对微粒体进行光亲和标记是否会对蛋白转运到微粒体以及在微粒体内的折叠产生不同影响这一问题。与两个亚基前体的转运相比，异二聚体荧光素酶折叠成天然状态对叠氮基-ATP更为敏感。因此，我们得出结论，在内质网中负责蛋白质折叠对ATP依赖性的微粒体蛋白对8-叠氮基-ATP光亲和标记敏感，且这种微粒体蛋白与参与蛋白质转运的微粒体ATP结合蛋白不同。
