Vascular endothelial cadherin (VE-cadherin): cloning and role in endothelial cell-cell adhesion.

OBJECTIVE

To identify proteins responsible for intercellular junction integrity in human umbilical vein endothelial cells (HUVEC), we produced a monoclonal antibody that recognized an endothelial cell-specific, junctionally restricted protein. We characterized and cloned the antigen to study its functional properties.

METHODS

The size and cellular distribution of the antigen were determined by immunofluorescence and immunoprecipitation. The molecule was cloned and transfected into cell lines, and its role in cell-cell adhesion and growth rate was determined.

RESULTS

Monoclonal antibody hec1 recognizes VE-cadherin, an endothelial cell-restricted cell adhesion molecule. VE-cadherin is localized to the borders between apposing endothelial cells but is diffusely distributed on subconfluent or migrating cells. Transfection of fibroblasts with VE-cadherin imparts to them the ability to adhere to each other in a calcium-dependent homophilic manner. Expression of VE-cadherin over a several-log range does not change the growth rate of these cells.

CONCLUSIONS

Despite the fact that VE-cadherin is a "nonclassical" cadherin by structure, it functions as a classic cadherin by imparting to cells the ability to adhere in a calcium-dependent, homophilic manner. On HUVEC it appears to play a role in maintaining monolayer integrity.