The quantification of hCLCA2 and colocalisation with integrin β4 in stratified human epithelia

Human calcium-activated chloride channel 2 (hCLCA2) belongs to a family of multifunctional proteins and is localised mainly in basal cells of squamous epithelia. However, its function is still not fully understood. Relative amounts of hCLCA2 were analysed using real-time PCR in several human epithelial tissues and tissues expressing high amounts were identified. These tissues then underwent double immunolabelling with anti-hCLCA2 antibodies and antibodies against the adhesion molecules integrin β4 and collagen VII and were visualised by fluorescence microscopy. Real-time PCR found hCLCA2 gene expression to be primarily associated with stratified squamous epithelia. Subsequent immunohistochemistry clearly demonstrated colocalisation between hCLCA2 and integrin β4. This study reports on a possible underlying relationship between hCLCA2 and stratified epithelia and the close association of hCLCA2 with basal cell adhesion molecules in normal tissue, suggesting it may play an important role in basal cell attachment in stratified epithelia.