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von Willebrand factor storage and multimerization: 2 independent intracellular processes
S L Haberichter1, S A Fahs, R R Montgomery
1Blood Research Institute, The Blood Center of Southeastern Wisconsin, Milwaukee, WI, USA.
Blood
|August 29, 2000
Summary
The von Willebrand factor propeptide (vW AgII) is essential for von Willebrand factor (vWF) multimerization and storage. These processes are independent, with vW AgII directing vWF trafficking to storage granules.
Area of Science:
- Hematology
- Cell Biology
- Molecular Biology
Background:
- The von Willebrand factor propeptide (vW AgII) plays a role in von Willebrand factor (vWF) multimerization and intracellular sorting.
- It remains unclear whether vWF multimerization and storage are independent processes.
Purpose of the Study:
- To investigate the independence of vWF multimerization and storage.
- To define the roles of vW AgII in these processes using chimeric constructs.
Main Methods:
- Development of chimeric constructs of human and canine von Willebrand factor (vWF).
- Expression of constructs in cells (AtT-20) to analyze vWF multimerization and storage.
- Utilized in trans and cis expression systems to study vW AgII and vWF interactions.
Main Results:
- Cells expressing mature vWF (Deltapro) alone produced non-stored vWF dimers.
- vW AgII alone was stored in granules.
- Co-expression of vW AgII and Deltapro led to vWF multimerization and co-localized storage.
- Canine vW AgII facilitated human vWF multimerization but not storage, while canine vWF was stored.
Conclusions:
- vWF multimerization and storage are distinct, independent intracellular processes.
- vW AgII contains signals necessary for vWF trafficking and granular storage.
- vWF requires interaction with vW AgII for chaperoning into storage granules.
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