Dynamin-2 is a novel NOS1[Beta] interacting protein and negative regulator in the collecting duct

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 NOS1... and its truncated variant NOS1..., while NOS1... predominates in mouse collecting ducts. We reporte...

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Bibliographic Details
Published in:American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2016-04, Vol.310 (7), p.R570
Main Authors: Hyndman, Kelly A, Arguello, Alexandra M, Morsing, Sofia KH, Pollock, Jennifer S
Format: Article
Language:English
Subjects:
Electrolytes
Experiments
Gene expression
Nitric oxide
Proteins
Rodents
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Summary: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 NOS1... and its truncated variant NOS1..., while NOS1... predominates in mouse collecting ducts. We reported that dynamin-2 (DNM2), a protein involved in excising vesicles from the plasma membrane, and NOS1... form a protein-protein interaction that promotes NO production in rat collecting ducts. NOS1... was found to be highly expressed in human renal cortical/medullary samples; hence, we tested the hypothesis that DNM2 is a positive regulator of NOS1...-derived NO production. COS7 and mouse inner medullary collecting duct-3 (mIMCD3) cells were transfected with NOS1... and/or DNM2. Coimmunoprecipitation experiments show that NOS1... 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/NOS1... 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. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0363-6119
1522-1490