Mutant Tyr87Ser-VWFpp facilitation of intracellular storage of VWF.

The mutant Tyr87Ser-VWFpp functions in trans to facilitate intracellular storage of VWF. The Tyr87Ser-VWFpp was coexpressed in trans with Δpro (mature VWF) as 2 separate plasmids. The fixed and permeabilized cells were immunolabeled as described in “Materials and methods.” Transfected cells were labeled with anti-VWF polyclonal antibodies (detected by FITC) and anti-VWFpp monoclonal antibodies (detected by TXR) to visualize the intracellular localization of VWF and VWFpp. Panel A shows anti-VWFpp staining (red); panel C shows anti-VWF staining (green); and panel B represents the merge of VWFpp and VWF (colocalization is shown in yellow). Tyr87Ser-VWFpp directs mature VWF into storage granules.