Title : Effect of sialic acid removal on VE-cadherin organization
Abstract :
Treatment of cultured endothelial cells with sialidase caused a complete loss of sialic acids from both the intercellular junctions and cell surface proteins without a loss of monolayer integrity
This was revealed by double-staining of sialidase treated cells with MAA/SNA-lectins and anti- PECAM-1 antibodies (Figure 8E,F)
Under these conditions, VE-cadherin changed its continuous junctional distribution to a largely scattered morphology but was still localized at interendothelial junctions
Importantly, the VE-cadherin superstructure largely disappeared showing small protein clusters of various sizes indicating a loss of lateral adhesion between VE-cadherin molecules (Figure 7A,A1)
Similar results were obtained when sialidase treatment was carried out in the presence of protease inhibitors ruling out that this observation might be due to contaminant proteolytic activities of the enzyme used (data not shown)
In contrast, PECAM-1-immunostaining was completely maintained after sialidase treatment (Figure 8F) and demonstrated an intact endothelial cell monolayer in which the cells remained attached to each other