Figure 5.

Aggregation of full-length muPECAM-1 L cell transfectants with and without exposure to sodium othovanadate. Standard and mixed aggregation studies were performed with and without (1 mM) calcium and with and without 1 h of pretreatment with sodium orthovanadate in L cell transfectants of full-length muPECAM-1. In standard aggregation studies, (A) L cells expressing full-length huPECAM-1 demonstrated calcium-dependent aggregation under control conditions. Identical to the huPECAM-1 cells, exposure to orthovanadate, however, changed the aggregation pattern to one that was more robust and calcium independent. Bars represent mean values from at least three experiments. Error bars depict the standard error of the mean. In mixed aggregation assays (with 1 mM calcium), the transfectants of muPECAM-1 without exposure to vanadate formed mixed aggregates (heterophilic interaction) (B), while the cells expressing muPECAM-1 after 1 h of exposure to sodium orthovanadate formed primarily self-aggregates (homophilic interaction) (C). These data are representative of at least three experiments.