Identification of a mitochondrial targeting sequence in cathepsin D and its localization in mitochondria
Identification of a mitochondrial targeting sequence in cathepsin D and its localization in mitochondria
复制标题
组织蛋白酶 D 中线粒体靶向序列的鉴定及其在线粒体中的定位
DOI：
10.1016/j.bbrc.2023.03.016
复制
发表时间：
2023
影响因子：
3.1
通讯作者：
Arakawa Hirofumi
中科院分区：
文献类型：
--
作者：
Ikari Naoki;Arakawa Hirofumi
组织蛋白酶D（CTSD）是一种主要的溶酶体蛋白酶，其具有N-末端信号肽（氨基酸1-20）以使囊泡从内质网转运到溶酶体。在这里，我们报告了线粒体靶向序列和CTSD在细胞中的线粒体定位的可能性。用C-末端增强的绿色荧光蛋白标记的CTSD（EGFP-CTSD）的活细胞成像分析表明CTSD定位于线粒体。CTSD氨基酸21-35负责其线粒体定位，其表现出线粒体靶向序列的典型特征，并且在进化上是保守的。蛋白酶K保护试验和蔗糖梯度分析表明线粒体中存在少量内源性CTSD分子。这些结果表明，CTSD是一个双重靶向的蛋白质，可以定位在溶酶体和线粒体。
Cathepsin D (CTSD) is a major lysosomal protease harboring an N-terminal signal peptide (amino acids 1–20) to enable vesicular transport from endoplasmic reticulum to lysosomes. Here, we report the possibility of a mitochondrial targeting sequence and mitochondrial localization of CTSD in cells. Live-cell imaging analysis with C-terminal enhanced green fluorescent protein-tagged CTSD (EGFP-CTSD) indicated that CTSD localizes to mitochondria. CTSD amino acids 21–35 are responsible for its mitochondrial localization, which exhibit typical features of mitochondrial targeting sequences, and are evolutionarily conserved. A proteinase K protection assay and sucrose gradient analysis showed that a small population of endogenous CTSD molecules exists in mitochondria. These results suggest that CTSD is a dual-targeted protein that may localize in both lysosomes and mitochondria.