Essential role of a carboxyl‐terminal α‐helix motif in the secretion of coagulation factor XI
In: Journal of Thrombosis and Haemostasis, Jg. 19 (2021-04-01), S. 920-930
Online
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Zugriff:
Background Coagulation factor XI (FXI) is a plasma serine protease zymogen that contributes to hemostasis. However, the mechanism of its secretion remains unclear. Objective To determine the molecular mechanism of FXI secretion by characterizing a novel FXI mutant identified in a FXI-deficient Japanese patient. Patient/methods The FXI gene (F11) was analyzed by direct sequencing. Mutant recombinant FXI (rFXI) was overexpressed in HEK293 or COS-7 cells. Western blotting and enzyme-linked immunosorbent assay were performed to examine the FXI extracellular secretion profile. Immunofluorescence microscopy was used to investigate the subcellular localization of the rFXI mutant. Results We identified a novel homozygous frameshift mutation in F11 [c.1788dupC (p.E597Rfs*65)], resulting in a unique and extended carboxyl-terminal (C-terminal) structure in FXI. Although rFXI-E597Rfs*65 was intracellularly synthesized, its extracellular secretion was markedly reduced. Subcellular localization analysis revealed that rFXI-E597Rfs*65 was abnormally retained in the endoplasmic reticulum (ER). We generated a series of C-terminal-truncated rFXI mutants to further investigate the role of the C-terminal region in FXI secretion. Serial rFXI experiments revealed that a threonine at position 622, the fourth residue from the C-terminus, was essential for secretion. Notably, Thr622 engages in the formation of an α-helix motif, indicating the importance of the C-terminal α-helix in FXI intracellular behavior and secretion. Conclusion FXI E597Rfs*65 results in the pathogenesis of a severe secretory defect due to aberrant ER-to-Golgi trafficking caused by the lack of a C-terminal α-helix motif. This study demonstrates the impact of the C-terminal structure, especially the α-helix motif, on FXI secretion.
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Essential role of a carboxyl‐terminal α‐helix motif in the secretion of coagulation factor XI
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Autor/in / Beteiligte Person: | Tamura, Shogo ; Suzuki, Nobuaki ; Odaira, Koya ; Hayakawa, Yuri ; Kawashima, Fumika ; Suzuki, Atsuo ; Kanematsu, Takeshi ; Katsumi, Akira ; Matsushita, Tadashi ; Tokoro, Mahiru ; Okamoto, Shuichi ; Takagi, Akira ; Kojima, Tetsuhito ; Hayakawa, Fumihiko |
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Zeitschrift: | Journal of Thrombosis and Haemostasis, Jg. 19 (2021-04-01), S. 920-930 |
Veröffentlichung: | Elsevier BV, 2021 |
Medientyp: | unknown |
ISSN: | 1538-7836 (print) |
DOI: | 10.1111/jth.15242 |
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