Free thiol groups in von Willebrand factor (VWF) are required for its full function under physiological flow conditions

Solecka, Barbara; Weise, Christoph; Fuchs, Birte; Kannicht, Christoph

doi:10.1016/j.thromres.2015.10.037

Cited by 5 publications

(7 citation statements)

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“…Furthermore, our simulations (which fully include non-covalent interactions in an explicit water model) suggest that such details do not seem to play a significant role deciding on the reacting species for IG27*, further confirming the generality of the proximity rule. Thiol-disulfide exchange upon forced unfolding has been recently observed for a growing number of proteins such as von Willebrand factor 17 , 18 , 38 . Whether they follow the same mechanism proposed here for I27* remains to be elucidated.…”

Section: Discussionmentioning

confidence: 99%

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Accessibility explains preferred thiol-disulfide isomerization in a protein domain

Kolšek

Aponte-Santamaría

Gräter

2017

Sci Rep

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Disulfide bonds are key stabilizing and yet potentially labile cross-links in proteins. While spontaneous disulfide rearrangement through thiol-disulfide exchange is increasingly recognized to play an important physiological role, its molecular determinants are still largely unknown. Here, we used a novel hybrid Monte Carlo and Molecular Dynamics scheme to elucidate the molecular principles of thiol-disulfide exchange in proteins, for a mutated immunoglobulin domain as a model system. Unexpectedly, using simple proximity as the criterion for thiol-disulfide exchange, our method correctly predicts the experimentally observed regiospecificity and selectivity of the cysteine-rich protein. While redox reactivity has been examined primarily on the level of transition states and activation barriers, our results argue for accessibility of the disulfide by the attacking thiol given the highly dynamic and sterically demanding protein as a major bottleneck of thiol-disulfide exchange. This scenario may be similarly at play in other proteins with or without an evolutionarily designed active site.

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Section: Discussionmentioning

confidence: 99%

“…This enormous multimer is critically involved in primary hemostasis and is particularly rich in cysteines and disulfide bonds. Current data points toward disulfide shuffling triggered by shearing of the protein 14 , 17 , 18 .…”

Section: Introductionmentioning

confidence: 99%

Accessibility explains preferred thiol-disulfide isomerization in a protein domain

Kolšek

Aponte-Santamaría

Gräter

2017

Sci Rep

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“…16 Finally, VWF contains free thiol groups in unpaired cysteines that can exchange with nearby disulfide groups to promote lateral selfassociation. 17,18 In particular, this has been demonstrated for Cys2431-Cys2453 and the nearby Cys2451-Cys2468 in the VWF C2 domain using small recombinant VWF constructs. 17 Using maleimide-biotin and N-ethylmaleimide as pharmacological inhibitors, such thiol-disulfide exchange has been proposed to control both VWF-platelet binding 19 and VWF-platelet cluster formation on endothelial cells.…”

Section: Introductionmentioning

confidence: 89%

von Willebrand factor self-association is regulated by the shear-dependent unfolding of the A2 domain

2019

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von Willebrand factor (VWF) self-association results in the homotypic binding of VWF upon exposure to fluid shear. The molecular mechanism of this process is not established. In this study, we demonstrate that the shear-dependent unfolding of the VWF A2 domain in the multimeric protein is a major regulator of protein self-association. This mechanism controls self-association on the platelet glycoprotein Ibα receptor, on collagen substrates, and during thrombus growth ex vivo. In support of this, A2-domain mutations that prevent domain unfolding due to disulfide bridging of N- and C-terminal residues (“Lock-VWF”) reduce self-association and platelet activation under various experimental conditions. In contrast, reducing assay calcium concentrations, and 2 mutations that destabilize VWF-A2 conformation by preventing coordination with calcium (D1498A and R1597W VWD type 2A mutation), enhance self-association. Studies using a panel of recombinant proteins that lack the A1 domain (“ΔA1 proteins”) suggest that besides pure homotypic A2 interactions, VWF-A2 may also engage other protein domains to control self-association. Addition of purified high-density lipoprotein and apolipoprotein-A1 partially blocked VWF self-association. Overall, similar conditions facilitate VWF self-association and ADAMTS13-mediated proteolysis, with low calcium and A2 disease mutations enhancing both processes, and locking-A2 blocking them simultaneously. Thus, VWF appears to have evolved 2 balancing molecular functions in a single A2 functional domain to dynamically regulate protein size in circulation: ADAMTS13-mediated proteolysis and VWF self-association. Modulating self-association rates by targeting VWF-A2 may provide novel methods to regulate the rates of thrombosis and hemostasis.

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“…Multimer biosynthesis is completed in WPB's but VWF processing does not end with its secretion. For example can high shear flow induce exposure of the above mentioned unpaired cysteines leading to covalent association via interchain disulfide bonds (97,98). This lateral self-association was suggested to align multiple VWF A1 domains thereby increasing binding avidity and bond strength for platelet GPIb (98,99) and collagen type III (98).…”

Section: In Circulationmentioning

confidence: 99%

Von Willebrand factor processing

Brehm¹

2017

Hamostaseologie

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Von Willebrand factor (VWF) is a multimeric glycoprotein essential for primary haemostasis that is produced only in endothelial cells and megakaryocytes. Key to VWF's function in recruitment of platelets to the site of vascular injury is its multimeric structure. The individual steps of VWF multimer biosynthesis rely on distinct posttranslational modifications at specific pH conditions, which are realized by spatial separation of the involved processes to different cell organelles. Production of multimers starts with translocation and modification of the VWF prepropolypeptide in the endoplasmic reticulum to produce dimers primed for glycosylation. In the Golgi apparatus they are further processed to multimers that carry more than 300 complex glycan structures functionalized by sialylation, sulfation and blood group determinants. Of special importance is the sequential formation of disulfide bonds with different functions in structural support of VWF multimers, which are packaged, stored and further processed after secretion. Here, all these processes are being reviewed in detail including background information on the occurring biochemical reactions.

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Free thiol groups in von Willebrand factor (VWF) are required for its full function under physiological flow conditions

Cited by 5 publications

References 50 publications

Accessibility explains preferred thiol-disulfide isomerization in a protein domain

Accessibility explains preferred thiol-disulfide isomerization in a protein domain

von Willebrand factor self-association is regulated by the shear-dependent unfolding of the A2 domain

Von Willebrand factor processing

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