Aquaporin 10 (AQP10)

Sequence analysis predicted that the 264-amino acid AQP10 protein, which is approximately 53% identical to AQP3 and AQP9, contains a cytosolic N terminus and 6 membrane-spanning domains with 5 connecting loops. The second and fifth loops possess the NPA motif, and there are 2 potential N-glycosylation sites in the third loop. The short cytoplasmic C terminus has a potential phosphorylation site. Northern blot analysis revealed expression of a 2.3-kb AQP10 transcript in jejunum but not liver. RNase protection analysis detected nearly exclusive expression in duodenum and jejunum. In situ hybridization analysis demonstrated highest expression of AQP10 in absorptive epithelial cells at the tips of villi in the jejunum. SDS-PAGE analysis showed expression of a 28-kD AQP10 protein, similar to its predicted size as well as to that of the other AQPs.