| First Author | Moeller HB | Year | 2016 |
| Journal | J Biol Chem | Volume | 291 |
| Issue | 5 | Pages | 2469-84 |
| PubMed ID | 26645691 | Mgi Jnum | J:230931 |
| Mgi Id | MGI:5766562 | Doi | 10.1074/jbc.M115.691121 |
| Citation | Moeller HB, et al. (2016) Regulation of the Water Channel Aquaporin-2 via 14-3-3theta and -zeta. J Biol Chem 291(5):2469-84 |
| abstractText | The 14-3-3 family of proteins are multifunctional proteins that interact with many of their cellular targets in a phosphorylation-dependent manner. Here, we determined that 14-3-3 proteins interact with phosphorylated forms of the water channel aquaporin-2 (AQP2) and modulate its function. With the exception of sigma, all 14-3-3 isoforms were abundantly expressed in mouse kidney and mouse kidney collecting duct cells (mpkCCD14). Long-term treatment of mpkCCD14 cells with the type 2 vasopressin receptor agonist dDAVP increased mRNA and protein levels of AQP2 alongside 14-3-3beta and -zeta, whereas levels of 14-3-3eta and -theta were decreased. Co-immunoprecipitation (co-IP) studies in mpkCCD14 cells uncovered an AQP2/14-3-3 interaction that was modulated by acute dDAVP treatment. Additional co-IP studies in HEK293 cells determined that AQP2 interacts selectively with 14-3-3zeta and -theta. Use of phosphatase inhibitors in mpkCCD14 cells, co-IP with phosphorylation deficient forms of AQP2 expressed in HEK293 cells, or surface plasmon resonance studies determined that the AQP2/14-3-3 interaction was modulated by phosphorylation of AQP2 at various sites in its carboxyl terminus, with Ser-256 phosphorylation critical for the interactions. shRNA-mediated knockdown of 14-3-3zeta in mpkCCD14 cells resulted in increased AQP2 ubiquitylation, decreased AQP2 protein half-life, and reduced AQP2 levels. In contrast, knockdown of 14-3-3theta resulted in increased AQP2 half-life and increased AQP2 levels. In conclusion, this study demonstrates phosphorylation-dependent interactions of AQP2 with 14-3-3theta and -zeta. These interactions play divergent roles in modulating AQP2 trafficking, phosphorylation, ubiquitylation, and degradation. |
