Involvement of PDZ-SAP97 interactions in regulating AQP2 translocation in response to vasopressin in LLC-PK1cells
| Autor: | Ajay Kale, Mohammed M. Nooh, Suleiman W. Bahouth |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Vasopressin urogenital system Physiology Chemistry PDZ domain Chromosomal translocation urologic and male genital diseases Cell biology law.invention 03 medical and health sciences 030104 developmental biology 0302 clinical medicine Membrane LLC-PK1 Cell Aquaporin 2 Confocal microscopy law 030220 oncology & carcinogenesis Phosphorylation |
| Zdroj: | American Journal of Physiology-Renal Physiology. 317:F375-F387 |
| ISSN: | 1522-1466 1931-857X |
| DOI: | 10.1152/ajprenal.00228.2018 |
| Popis: | Arginine-vasopressin (AVP)-mediated translocation of aquaporin-2 (AQP2) protein-forming water channels from storage vesicles to the membrane of renal collecting ducts is critical for the renal conservation of water. The type-1 PDZ-binding motif (PBM) in AQP2, “GTKA,” is a critical barcode for its translocation, but its precise role and that of its interacting protein partners in this process remain obscure. We determined that synapse-associated protein-97 (SAP97), a membrane-associated guanylate kinase protein involved in establishing epithelial cell polarity, was an avid binding partner to the PBM of AQP2. The role of PBM and SAP97 on AQP2 redistribution in response to AVP was assessed in LLC-PK1renal collecting cells by confocal microscopy and cell surface biotinylation techniques. These experiments indicated that distribution of AQP2 and SAP97 overlapped in the kidneys and LLC-PK1cells and that knockdown of SAP97 inhibited the translocation of AQP2 in response to AVP. Binding between AQP2 and SAP97 was mediated by specific interactions between the second PDZ of SAP97 and PBM of AQP2. Mechanistically, inactivation of the PBM of AQP2, global delocalization of PKA, or knockdown of SAP97 inhibited AQP2 translocation as well as AVP- and forskolin-mediated phosphorylation of Ser256in AQP2, which serves as the major translocation barcode of AQP2. These results suggest that the targeting of PKA to the microdomain of AQP2 via SAP97-AQP2 interactions in association with cross-talk between two barcodes in AQP2, namely, the PBM and phospho-Ser256, plays an important role in the translocation of AQP2 in the kidney. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|