Baqui M M, Gereben B, Harney J W, Larsen P R, Bianco A C
Department of Medicine, Brigham and Women 's Hospital, Harvard Medical School, Boston, MA, USA.
Endocrinology. 2000 Nov;141(11):4309-12. doi: 10.1210/endo.141.11.7872.
We compared the subcellular localization of FLAG-epitope tagged Types 1 and 2 deiodinases (D1 and D2) transiently expressed in human embryonic kidney (HEK-293) and mouse neuroblastoma (NB2A) cells. D2 is an integral membrane protein based on resistance to extraction at pH 11 with the NH2 terminus in the endoplasmic reticulum (ER). Immunofluorescence confocal microscopy using anti-FLAG and anti-GRP78/BiP antibodies showed the FLAG-D1 signal was found in the periphery of the cells and not co-localized with the ER specific marker GRP78/BiP. On the other hand, FLAG-D2 protein was found in the ER co-localized with the GRP78/BiP protein. These differential distribution patterns indicate subcellular sorting of D1 and D2 is determined by intrinsic protein sequence and can explain the ready access of D2-generated T3 to the nucleus.
我们比较了在人胚肾（HEK - 293）细胞和小鼠神经母细胞瘤（NB2A）细胞中瞬时表达的带有FLAG表位标签的1型和2型脱碘酶（D1和D2）的亚细胞定位。基于在pH 11时对内质网（ER）中NH2末端提取的抗性，D2是一种整合膜蛋白。使用抗FLAG和抗GRP78 / BiP抗体进行的免疫荧光共聚焦显微镜检查显示，FLAG - D1信号出现在细胞周边，且不与ER特异性标志物GRP78 / BiP共定位。另一方面，FLAG - D2蛋白在内质网中被发现，并与GRP78 / BiP蛋白共定位。这些不同的分布模式表明，D1和D2的亚细胞分选是由内在蛋白质序列决定的，并且可以解释D2产生的T3易于进入细胞核的原因。
