Fig. 1.

Diagrammatic representations of claudin-16. a The protein contains four TMDs (1–4) and two ECSs (1–2). ECS1 contains the ion selectivity filter while ECS2 is involved in claudin–claudin interactions. The location of the mutations included in this study is indicated. b Hypothetical protein structures of mutant claudin-16 proteins translated from the aberrant transcripts detected in Fig. 3a. Truncated exon 3 induced by mutations c.446G > T and c.453G > T would result in loss of the terminal part of ECS1 and part of TMD2. Skipping of exon 3 produced by mutation c.571G > A would cause loss of the terminal part of ECS1, TMD2, the cytoplasmic region and part of TMD3. Skipping of exon 4 induced mutations c.593G > A and c593G > C would result in loss of part of TMD3, ECS2, TMD4, and part of the cytoplasmic C terminus