The rat Pkd2 protein assumes distinct subcellular distributions in different organs

Mutations in the PKD2 gene account for similar to 15% of all cases of autos omal-dominant polycystic kidney disease. In the present study the cellular distribution of the Pkd2 protein was investigated by immunohistochemistry i n different rat organs. Although the Pkd2 protein showed a widespread expre ssion, a strikingly different distribution of the protein was observed betw een individual organs. Whereas in renal distal tubules and in striated duct s of salivary glands a basal-to-basolateral distribution of Pkd2 was found, a punctate cytoplasmic location was detected in the adrenal gland, ovary, cornea, and smooth muscle cells of blood vessels. Interestingly, in the adr enal gland and ovary, the rat Pkd2 protein was more heavily N-glycosylated than in the kidney and salivary gland. These results suggest that Pkd2 acco mplishes its functions by interacting with proteins located in different ce llular compartments. The extrarenal expression pattern of the Pkd2 protein hints at other candidate sites of disease manifestations in patients carryi ng PKD2 mutations.