Predominantly expressed in the sublingual salivary gland, in the mucous cells of the acini, but not in the serous cells, nor in the duct system (at protein level). Not detected in the submandilar, nor the parotid glands. Expressed in the mucous glands, but not detected in the serous glands (at protein level). Besides the salivary glands, expressed in the Brunner's glands in the duodenum, but no other mucous or serous glands (at protein level).