Sialic Acid Acetylesterase (SIAE)

SIAE appears to encode both lysosomal and cytosolic sialic acid acetylesterase isoforms. The deduced 523-amino acid protein has a calculated molecular mass of 58 kD. It contains a putative N-terminal signal sequence and shares significant similarity with mouse Lse. Northern blot analysis detected a 2.7-kb transcript in all tissues examined, with highest expression in testis, prostate, and colon. A 6.0-kb transcript was expressed highly in testis and at lower levels in colon, small intestine, prostate, and thymus. A 7.5-kb transcript was expressed exclusively in colon. In situ hybridization of human embryonic and adult testis detected LSE only in adult testis, where it was restricted to germ cells. Fluorescence-tagged LSE localized to lysosomes in a transfected human pancreatic carcinoma cell line.