Molecular cloning reveals alternative splice forms of human α(E)-Catenin

At least three proteins (α, β, and γ catenin) comprise the cytoplasmic domain of the cadherin cell-cell adhesion complex. We have cloned and sequenced human epithelial α(E)-catenin and have identified two distinct transcripts, designated α₁- and α₂-. The human α₁(E)-catenin transcript predicts a 907 aa sequence 97% identical to mouse α-catenin. The second transcript, α₂(E)-catenin, displays a 24 amino acid insertion after codon 812, yielding a 931 amino acid protein (GenBank #L23805). Analysis by RT-PCR and Northern blotting detects one or both transcripts in epithelial and non-epithelial tissues. Southern blotting indicates that both arise from a single gene. The alternative transcription site in α-catenin is analogous to the splice site in vinculin that creates metα-vinculin, extending the homology between α-catenin and vinculin. These data with the reported structure of other catenin genes suggest that vinculin and α-catenin generate a superfamily of proteins mediating membrane-cytoskeletal associations.