Figure 1.

Multiple sequence alignments for the members of the claudin family. Putative membrane-spanning domains are represented by bars. Residues conserved in at least six of the eight sequences are highlighted with black backgrounds. The amino acid sequence was fairly conserved in the first and fourth transmembrane domains as well as in the first and second extracellular loops but was diversified in the second and third transmembrane domains. Note that all of the claudin family members end in -Y-V at their COOH-termini. The nucleotide sequence data of mouse claudin-1 to -8 are available from European Molecular Biology Laboratory/GenBank database/DNA Data Base in Japan under accession numbers AF072127, AF072128, AF087821, AF087822, AF087823, AF087824, AF087825, and AF087826, respectively.