Interspecies diversity of chloride channel regulators, calcium-activated 3 genes
Fig 5
Predicted protein structure of feline CLCA3 and detection of its amino-terminal cleavage product in the respiratory tract and esophagus.
(A) The amino acid sequence of feline CLCA3 contains a cleavable signal sequence (black box), an amino-terminal CLCA domain (n-CLCA) followed by a von Willebrand factor type A domain (vWA). No potential transmembrane domain was predicted. Several sites for N-linked glycosylation were predicted (asterisks). The arrow denotes the putative proteolytic cleavage site at 702 aa. aa, amino acids. (B) A 90-kDa protein was detected with the anti-feline CLCA3 antibodies by immunoblotting in the trachea. Much stronger CLCA3 expression was found in the esophagus. The protein was undetectable in the stomach, here shown as tissue without CLCA3 protein expression, as expected from mRNA results. The antibody also detected an approximately 40 kDa band in the tissue lysate of trachea and esophagus, however, these bands were also detected by the irrelevant antibody (S1 Fig). An antibody to beta-actin was used as a loading control (lower panel).