Multimeric analysis of heterozygous expression of type 2A VWF variants with WT-VWF. VWF variants with a mycHis tag were coexpressed 1:1 with WT-VWF (heterozygous) or with mock (homozygous). VWF in the conditioned medium of transiently transfected HEK293T cells was analyzed by electrophoresis in 2% SDS-agarose gels and immunoblotted as described in “Multimer analysis.” All samples were run on the same gel and lanes were removed for clarity, as denoted by the white space. (A) Immunoblot for the mycHis tag. (B) Immunoblot using Ab AVW-5 that does not recognize mycHis-tagged VWF. (C) Overlay of panels A and B for total VWF. Lane 1 is supernatant from mock-transfected cells. Lanes 2-4 show WT-VWF proteins with and without myc His tags to demonstrate Ab specificity. In lanes 5-16, data are shown in pairs, with one lane showing the mycHis-tagged type 2A variant cotransfected with mock (homozygous) or with untagged WT-VWF (heterozygous). Some type 2A variants have a negative impact on WT-VWF multimerization.