Loss of glycosylation at N857 causes intracellular degradation by the proteasome. (A) Wild-type VWF and VWF-N857Q were expressed in the absence or presence of 10μM Lactacystin and expression analyzed by VWF ELISA Secreted media (■) and cell lysate (□). (B) HEK293T cells transfected with VWF-N857Q and subjected to pulse chase analysis in the absence or presence of 10μM Lactacystin. Cell lysates were immunoprecipitated and analyzed as described in “Methods.” *: Pro-VWF, ■: mature VWF.