| First Author | Hyndman KA | Year | 2016 |
| Journal | Am J Physiol Regul Integr Comp Physiol | Volume | 310 |
| Issue | 7 | Pages | R570-7 |
| PubMed ID | 26791826 | Mgi Jnum | J:230822 |
| Mgi Id | MGI:5766102 | Doi | 10.1152/ajpregu.00008.2015 |
| Citation | Hyndman KA, et al. (2016) Dynamin-2 is a novel NOS1beta interacting protein and negative regulator in the collecting duct. Am J Physiol Regul Integr Comp Physiol 310(7):R570-7 |
| abstractText | Nitric oxide synthase 1 (NOS1)-derived nitric oxide (NO) production in collecting ducts is critical for maintaining fluid-electrolyte balance. Rat collecting ducts express both the full-length NOS1alpha and its truncated variant NOS1beta, while NOS1beta predominates in mouse collecting ducts. We reported that dynamin-2 (DNM2), a protein involved in excising vesicles from the plasma membrane, and NOS1alpha form a protein-protein interaction that promotes NO production in rat collecting ducts. NOS1beta was found to be highly expressed in human renal cortical/medullary samples; hence, we tested the hypothesis that DNM2 is a positive regulator of NOS1beta-derived NO production. COS7 and mouse inner medullary collecting duct-3 (mIMCD3) cells were transfected with NOS1beta and/or DNM2. Coimmunoprecipitation experiments show that NOS1beta and DNM2 formed a protein-protein interaction. DNM2 overexpression decreased nitrite production (index of NO) in both COS7 and mIMCD-3 cells by 50-75%. mIMCD-3 cells treated with a panel of dynamin inhibitors or DNM2 siRNA displayed increased nitrite production. To elucidate the physiological significance of IMCD DNM2/NOS1beta regulation in vivo, flox control and CDNOS1 knockout mice were placed on a high-salt diet, and freshly isolated IMCDs were treated acutely with a dynamin inhibitor. Dynamin inhibition increased nitrite production by IMCDs from flox mice. This response was blunted (but not abolished) in collecting duct-specific NOS1 knockout mice, suggesting that DNM2 also negatively regulates NOS3 in the mouse IMCD. We conclude that DNM2 is a novel negative regulator of NO production in mouse collecting ducts. We propose that DNM2 acts as a "break" to prevent excess or potentially toxic NO levels under high-salt conditions. |
