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Dependence on Vitam...
Dependence on Vitamin K-dependent Protein S for Eukaryotic Cell Secretion of the β-Chain of C4b-binding Protein
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- Carlsson, Sofia (författare)
- Lund University, Sweden;Skåne University Hospital, Sweden
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- Dahlbäck, Björn (författare)
- Lund University, Sweden;Skåne University Hospital, Sweden
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(creator_code:org_t)
- The American Society for Biochemistry and Molecular Biology, 2010
- 2010
- Engelska.
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Ingår i: Journal of Biological Chemistry. - : The American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 285:42, s. 32038-32046
- Relaterad länk:
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https://doi.org/10.1...
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visa fler...
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http://www.jbc.org/c...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The anticoagulant vitamin K-dependent protein S (PS) circulates in plasma in two forms, 30% free and 70% being bound to the complement regulatory protein C4b-binding protein (C4BP). The major C4BP isoform consists of 7 α-chains and 1 β-chain (C4BPβ+), the chains being linked by disulfide bridges. PS binds to the β-chain with high affinity. In plasma, PS is in molar excess over C4BPβ+ and due to the high affinity, all C4BPβ+ molecules contain a bound PS. Taken together with the observation that PS-deficient patients have decreased levels of C4BPβ+, this raises the question of whether PS is important for secretion of the β-chain from the cell. To test this hypothesis, HEK293 cells were stably and transiently transfected with β-chain cDNA in combinations with cDNAs for PS and/or the α-chain. The concentration of β-chains in the medium increased after co-transfection with PS cDNA, but not by α-chain cDNA, suggesting secretion of the β-chains from the cells to be dependent on concomitant synthesis of PS, but not of the α-chains. Thus, β-chains that were not disulfide-linked to the α-chains were secreted in complex with PS, either as monomers or dimers. Pulse-chase demonstrated that the complexes between PS and β-chain were formed intracellularly, in the endoplasmic reticulum. In conclusion, our results demonstrate that successful secretion of β-chains depends on intracellular complex formation with PS, but not on the α-chains. This provides an explanation for the decreased β-chain levels observed in PS-deficient patients.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Klinisk laboratoriemedicin (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Clinical Laboratory Medicine (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinsk bioteknologi -- Biomedicinsk laboratorievetenskap/teknologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Medical Biotechnology -- Biomedical Laboratory Science/Technology (hsv//eng)
- NATURVETENSKAP -- Biologi -- Cellbiologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Cell Biology (hsv//eng)
Nyckelord
- Biomedical Sciences
- Biomedicinsk vetenskap
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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