Protein S-Leu17Pro disrupts the hydrophobicity of its signal peptide causing a proteasome-dependent degradation

Autor: Kentaro Okada, Shogo Tamura, Nobuaki Suzuki, Koya Odaira, Masato Mukaide, Wataru Fujii, Yumi Katsuragi, Atsuo Suzuki, Takeshi Kanematsu, Shuichi Okamoto, Naruko Suzuki, Akira Katsumi, Tadashi Matsushita, Tetsuhito Kojima, Fumihiko Hayakawa
Rok vydání: 2021
Předmět:
Zdroj: Thrombosis research. 210
ISSN: 1879-2472
Popis: Protein S is a vitamin K-dependent glycoprotein with important anticoagulant, fibrinolytic, anti-inflammatory, anti-apoptotic, and cytoprotective functions. Congenital protein S deficiency is an autosomal dominant thrombophilia due to protein S gene (PROS1) variations. Our group identified a variation in PROS1 that translates into protein S deficiency: c.50 T C (p.Leu17Pro). Here, we investigated the mechanisms by which this variation results in protein S deficiency.The effect of L17P substitution on protein S signal peptide was predicted by in silico (a computational prediction technique) analysis of hydrophobicity and signal peptide cleavage. Recombinant protein S was overexpressed in HEK293 and COS-7 cells. Intracellular kinetics and extracellular secretion of recombinant protein S-L17P were analyzed by western blotting and immunocytochemistry.In silico hydrophobicity analysis showed that protein S-L17P had disrupted hydrophobic status in the h-region of its signal peptide. Under normal culture conditions, recombinant protein S -L17P was not detected in either transfectant cell lysates or medium. Upon treatment with a proteasome inhibitor, recombinant protein S-L17P was clearly detected in the cell lysate, but not in the culture medium. Recombinant protein S-L17P did not undergo post-translational modification with N-glycosylation, suggesting that the nascent polypeptide of recombinant protein S-L17P is not transported to the endoplasmic reticulum lumen, but is mislocalized to the cytosol.PROS1-L17P variation translates into protein S deficiency. Protein S-L17P causes its cytosolic mislocalization resulting in its proteasome-dependent degradation.
Databáze: OpenAIRE
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