Intracellular trafficking of factor VIII to von Willebrand factor storage granules.
نویسندگان
چکیده
In plasma, von Willebrand factor (vWf) associates with Factor VIII (FVIII); however, the site at which these proteins first interact has not been defined. Administration of 1-desamino-8-D-arginine vasopressin (DDAVP) causes a rapid, concomitant elevation in plasma levels of both vWf and FVIII, suggesting the existence of a DDAVP-releasable storage pool for both proteins. To determine whether vWf and FVIII can associate intracellularly and colocalize to storage vesicles, we transfected AtT-20 cells with vWf and FVIII expression plasmids. FVIII alone was not detectable within storage granules; however, transfection of vWf cDNA into the same cell caused FVIII to alter its intracellular trafficking and to undergo granular storage, colocalizing to the vWf-containing granules. In contrast, colocalization of FVIII was not observed when these cells were transfected with plasmids encoding defective FVIII-binding vWf mutants. Transfection of bovine endothelial cells with FVIII further demonstrated vesicular storage of FVIII with vWf in Weibel-Palade bodies. Since gene therapy of hemophilia A may ultimately target endothelium or hematopoietic stem cells, the interaction between vWf and FVIII within a secretory cell is important. Thus, vWf can alter the intracellular trafficking of FVIII from a constitutive to a regulated secretory pathway, thereby producing an intracellular storage pool of both proteins.
منابع مشابه
von Willebrand factor storage and multimerization: 2 independent intracellular processes.
The von Willebrand factor propeptide, vW AgII, has been shown to be required for the formation of vWF multimers and sorting of vWF to storage granules; whether these 2 processes are independent events has been unclear. Chimeric constructs of human and canine vWF were developed to further define these processes and to determine whether they are independent intracellular events. Cells expressing ...
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ورودعنوان ژورنال:
- The Journal of clinical investigation
دوره 101 3 شماره
صفحات -
تاریخ انتشار 1998