(a) Microarray-based expression screening of brain pericytes (BP), placenta pericytes (PP), pancreas pericytes (PA), lung pericytes (LP), muscle pericytes (MP) and human umbilical vein endothelial cells (HUVEC [HU]). (b) Semi-quantitative PCR of TEK (Tie2), endothelial marker genes (PECAM1, CDH5) and pericyte marker genes (CSPG4, CD248) in HUVEC and BP; house keeping gene: GAPDH. (c) Representative images showing expression of Tie2 in HUVEC and BP. (d) Histogram of membrane-bound Tie2 expression in HUVEC and BP compared to isotype control measured by flow cytometry. (e,g) Western blot (WB) analysis of tyrosine phosphorylation (pTyr) and total Tie2 after Tie2 immunoprecipitation (IP) in BP (e) and HUVEC (g) upon stimulation with recombinant human (rh) Ang1 compared to unstimulated (us) cells. (f,h) Quantification of the ratio of phosphorylated Tie2 (pTie2) relative to total Tie2 protein in BP (f) and HUVEC (h) normalized to us control (n=3). (i,k) Western blot analysis of AKT phosphorylation (Ser473) in control (shCtr) and Tie2-silenced (shTie2 I/shTie2 II) BP (i) and HUVEC (k) upon stimulation with rhAng1 or rhAng2. (j,l) Quantification of the ratio of pAKT to total AKT protein expression in BP (j) and HUVEC (l) normalized to unstimulated control (n=3). Representative western blot images are cropped versions and original images can be found in Supplementary Fig. 15. Scale bars: 20 μm (c). Data are shown as mean±s.d. Statistics were performed using Mann–Whitney U test (f,h) and one-way ANOVA (j,l). *P<0.05, **P<0.01.