TI - Examination of the effect of wild-type and mutant PKD2 on the JAK2/STAT-1/p21/Cdk2 pathway in NRK-52E cells . AB - HEK293 cells were generated by transformation of human embryonic kidney cell cultures with sheared adenovirus 5 DNA [33] . The cell line has an epithelial morphology and is widely used as a kidney epithelial model . Nevertheless , there is controversy as to whether these cells are of true kidney origin , since expression studies have demonstrated that HEK293 cells have an unexpected relationship with neurons [34] . For these reasons we decided to perform the same experiments in a different cell line system more closely resembling mature kidney epithelial cells , NRK-52E . The rat kidney epithelial cell line , NRK-52E was transiently transfected with vector-only ( CT ) , WT PKD2 , R742X PKD2 and 1-702 PKD2 ( a PKD2 mutant lacking the entire carboxy terminal region of the protein ) . At 48 hours after transfection , cells were synchronized by serum starvation . Whole cell lysates were immunoblotted with anti-p21 and anti-PHOSphorylated STAT-1 antibodies . Neither p21 levels nor STAT-1 PHOSphorylation is affected by expression of wild-type or mutant PKD2 (Figure 4A) . Similarly , the levels of active Cdk2 were comparable among the four transfectants . In addition to the JAK2/STAT-1/p21/Cdk2 pathway , the proliferation capacity of NRK-52E transfected with WT , R742X and 1-702 PKD2 appeared unaltered compared to vector only transfectants as judged by PCNA Western blot analysis . Good expression of the wild-type PC-2 and of the two truncated proteins was achieved as judged by anti-HA and anti-PC2 blotting . In summary , these results duplicate the observation in HEK293 that wild-type or mutant PKD2 expression do not modify the activity of the JAK2/STAT-1/p21/Cdk2 pathway .