Fig. 1.

Sequence and exogenous expression of claudin-5 (Cld5) constructs in stably transfected MDCK-II cells. a Predicted (swissprot) amino acid sequence of the second extracellular loop of mouse Cld5 wild type (wt) and its mutants. Amino acids substituted by site-directed mutagenesis are indicated in bold. b Schematic overview of Cld5 and the positions of the amino acid substitutions in the Cld5 mutants transfected. c Expression of the different Cld5 proteins in stably transfected MDCK-II cell lines. Cld5 was not detected in cells transfected with the vector control. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) served as loading control. d The expression of the exogenous Cld5 proteins did not influence the expression of endogenous claudin-1 (Cld1). For C and D, Cld5 and Cld1 were detected by Western blot of cell lysates