1. Positively charged cytoplasmic residues in corin prevent signal peptidase cleavage and endoplasmic reticulum retention
- Author
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Hui Li, Shijin Sun, Wenjun Guo, Lina Wang, Zihao Zhang, Yue Zhang, Ce Zhang, Meng Liu, Shengnan Zhang, Yayan Niu, Ningzheng Dong, and Qingyu Wu
- Subjects
Biology (General) ,QH301-705.5 - Abstract
Abstract Positively charged residues are commonly located near the cytoplasm-membrane interface, which is known as the positive-inside rule in membrane topology. The mechanism underlying the function of these charged residues remains poorly understood. Herein, we studied the function of cytoplasmic residues in corin, a type II transmembrane serine protease in cardiovascular biology. We found that the positively charged residue at the cytoplasm-membrane interface of corin was not a primary determinant in membrane topology but probably served as a charge-repulsion mechanism in the endoplasmic reticulum (ER) to prevent interactions with proteins in the ER, including the signal peptidase. Substitution of the positively charged residue with a neutral or acidic residue resulted in corin secretion likely due to signal peptidase cleavage. In signal peptidase-deficient cells, the mutant corin proteins were not secreted but retained in the ER. Similar results were found in the low-density lipoprotein receptor and matriptase-2 that have positively charged residues at and near the cytoplasm-membrane interface. These results provide important insights into the role of the positively charged cytoplasmic residues in mammalian single-pass transmembrane proteins.
- Published
- 2025
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