The invention provides a novel splice-variant of the ClC-4 protein, termed ClC-4A. ClC-4A is expressed in taste bud cells and is involved in sour taste perception. The invention provides ClC-4A polynucleotides and ClC-4A polypeptides, vectors, host cells and ClC-4A specific antibodies as well as designing high potency taste stimuli, determining taste preferences in animals, developing breed-specific foods, and modifying the taste of foods and medications.