Candidate gene selection and validation. Candidate genes were selected from a list of 75 MK-specific genes encoding transmembrane proteins. (A) Overlap analysis of MK-specific, present in HUVECs and transmembrane protein encoding genes. Of the 279 MK-specific genes, 143 are also present in HUVECs, and 35 of these encode transmembrane proteins. (B) Heatmap of log2 transformed, normalized intensity values for the 6 MK genes used in this study, showing increased expression of 4 in MKs and HUVECs. (C) Domain architecture of BAMBI, DCBLD2, ESAM, and LRRC32 as predicted using the Eukaryotic Linear Motif resource. The length of the black line represents the number of amino acids with domain positions to scale. Domain acronyms: CUB indicates complement C1r/C1s, Uegf, Bmp1; F5_F8, coagulation factor 5/8 type; IgSF, immunoglobulin fold; LCCL, Limulus factor C, Coch-5b2 and Lgl1; LRR_1, leucine rich repeats; LRRNT, leucine rich repeat N-terminal domain; SigP, signal peptide; TM, transmembrane domain.