Identification of a Polycystin-1 Cleavage Product, P100, That Regulates Store Operated Ca2+ Entry through Interactions with STIM1

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a genetic disorder resulting in large kidney cysts and eventual kidney failure. Mutations in either the PKD1 or PKD2/TRPP2 genes and their respective protein products, polycystin-1 (PC1) and polycystin-2 (PC2) result in ADPKD. PC2 is known to function as a non-selective cation channel, but PC1's function and the function of PC1 cleavage products are not well understood. Here we identify an endogenous PC1 cleavage product, P100, a 100 kDa fragment found in both wild type and epitope tagged PKD1 knock-in mice. Expression of full length human PC1 (FL PC1) and the resulting P100 and C-Terminal Fragment (CTF) cleavage products in both MDCK and CHO cells significantly reduces the store operated Ca2+ entry (SOCE) resulting from thapsigargin induced store depletion. Exploration into the roles of P100 and CTF in SOCE inhibition reveal that P100, when expressed in Xenopus laevis oocytes, directly inhibits the SOCE currents but CTF does not, nor does P100 when containing the disease causing R4227X mutation. Interestingly, we also found that in PC1 expressing MDCK cells, translocation of the ER Ca2+ sensor protein STIM1 to the cell periphery was significantly altered. In addition, P100 Co-immunoprecipitates with STIM1 but CTF does not. The expression of P100 in CHO cells recapitulates the STIM1 translocation inhibition seen with FL PC1. These data describe a novel polycystin-1 cleavage product, P100, which functions to reduce SOCE via direct inhibition of STIM1 translocation; a function with consequences for ADPKD

A new series of 1,3,4-oxadiazole linked quinolinyl-pyrazole/isoxazole derivatives: synthesis and biological activity evaluation

A series of 1,3,4-oxadiazole bridged pyrazole/isoxazole bearing quinoline derivatives has been designed and synthesized by a clean and convenient method. Structures of the newly synthesized compounds have been confirmed by FTIR, H-1 and C-13 NMR, and HRMS spectral data. The titled compounds have been evaluated for their molecular docking guided antimicrobial and anti-inflammatory activity. One of 1,3,4-oxadiazole bridged quinolinyl-pyrazole derivatives has interacted efficiently with E. Coli protein (PDB file: 1KZN), and has been characterized by good antimicrobial activity against the majority of the tested pathogens. Another product has exhibited excellent anti-inflammatory activity