Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Biochem Biophys Res Commun. 2010 Nov 26;402(4):588-94. doi: 10.1016/j.bbrc.2010.09.133. Epub 2010 Oct 20.
In a recent proteomic study of lysosomal proteins [10], we identified SID1 transmembrane family, member 2 (Sidt2) as a novel lysosomal membrane protein candidate. The Sidt2 gene encodes an 832-amino acid residues protein with a calculated molecular mass of 94.5kDa. Bioinformatic analysis showed that Sidt2 is a multipass transmembrane protein that contains 10 putative N-glycosylation sites (NxS/T) and two potential tyrosine-based sorting signals (YGSF and YDTL). Using specific anti-Sidt2 antibody and lysosomal markers, the lysosomal localization of Sidt2 was determined by immunofluorescence. Furthermore, using subcellular fractionation techniques, we demonstrated that Sidt2 is a lysosomal integral membrane protein. Endogenous Sidt2 was detected in multiple tissues of mouse and rat with approximately 120-130kDa molecular weights due to extensive glycosylation. After digestion with PNGase F, the apparent molecular mass of Sidt2 decreased to the predicted value of 95kDa. In rats, Sidt2 was highly expressed in the liver, brain, and kidney, whereas no or little expression was found in the skeletal muscles, heart, and other tissues. In summary, Sidt2 is a highly glycosylated lysosomal integral membrane protein that shows tissue-specific expression.
在最近的一项溶酶体蛋白的蛋白质组学研究中[10]，我们鉴定出 SID1 跨膜家族成员 2（Sidt2）是一种新的溶酶体膜蛋白候选物。Sidt2 基因编码一个由 832 个氨基酸残基组成的蛋白质，计算分子量为 94.5kDa。生物信息学分析表明，Sidt2 是一种多跨膜蛋白，含有 10 个潜在的 N-糖基化位点（NxS/T）和两个潜在的酪氨酸基分拣信号（YGSF 和 YDTL）。使用特异性的抗 Sidt2 抗体和溶酶体标记物，通过免疫荧光确定了 Sidt2 的溶酶体定位。此外，使用亚细胞分级分离技术，我们证明了 Sidt2 是一种溶酶体整合膜蛋白。由于广泛的糖基化，内源性 Sidt2 在小鼠和大鼠的多种组织中被检测到，分子量约为 120-130kDa。在用 PNGase F 消化后，Sidt2 的表观分子量降低到预测的 95kDa。在大鼠中，Sidt2 在肝脏、大脑和肾脏中高度表达，而在骨骼肌、心脏和其他组织中则没有或很少表达。总之，Sidt2 是一种高度糖基化的溶酶体整合膜蛋白，具有组织特异性表达。
