Medicine and Health Sciences Commons^™

Role Of Na/K-Atpase Non-Enzymatic Signaling In Renal Proximal Tubule Sodium Transport, Shreya Tapan Mukherji

Theses, Dissertations and Capstones

The renal proximal tubule (RPT) is the center stage for renal handling of Na+ , a potent determinant of systemic Na+ and volume homeostasis in health and disease. In the RPT, through its classic ion-pumping function, Na + /K+ -ATPase (NKA) generates the Na+ gradient that drives apical Na+ absorption, mostly through Na+ /H+ exchanger (NHE3). In contrast, pharmacological evidence suggests that the activation of the NKA non-enzymatic signaling function, through Src and other signaling partners, triggers a cellular redistribution of NKA and NHE3 that decreases transcellular Na+ flux in cultured RPT cells. However, the physiological relevance of the nonenzymatic …

Na/K-Atpase Signaling And Salt Sensitivity: The Role Of Oxidative Stress, Jiang Liu, Yanling Yan, Ying Nie

Biochemistry and Microbiology

Other than genetic regulation of salt sensitivity of blood pressure, many factors have been shown to regulate renal sodium handling which contributes to long-term blood pressure regulation and have been extensively reviewed. Here we present our progress on the Na/K-ATPase signaling mediated sodium reabsorption in renal proximal tubules, from cardiotonic steroids-mediated to reactive oxygen species (ROS)-mediated Na/K-ATPase signaling that contributes to experimental salt sensitivity.

Protein Carbonylation Of An Amino Acid Residue Of The Na/K‐Atpase Α1 Subunit Determines Na/K‐Atpase Signaling And Sodium Transport In Renal Proximal Tubular Cells, Yanling Yan, Anna P. Shapiro, Brahma R. Mopidevi, Muhammad Chaudhry, Kyle Maxwell, Steven T. Haller, Christopher A. Drummond, David J. Keendey, Jiang Tian, Deepak Malhorta, Zijian Xie, Joseph I. Shapiro Md, Jiang Liu

Biochemistry and Microbiology

Background We have demonstrated that cardiotonic steroids, such as ouabain, signaling through the Na/K‐ATPase, regulate sodium reabsorption in the renal proximal tubule. By direct carbonylation modification of the Pro222 residue in the actuator (A) domain of pig Na/K‐ATPase α1 subunit, reactive oxygen species are required for ouabain‐stimulated Na/K‐ATPase/c‐Src signaling and subsequent regulation of active transepithelial ²²Na⁺ transport. In the present study we sought to determine the functional role of Pro222 carbonylation in Na/K‐ATPase signaling and sodium handling.

Methods and Results Stable pig α1 knockdown LLC‐PK1‐originated PY‐17 cells were rescued by expressing wild‐type rat α1 and rat α1 with …

Carbonylation Modification Regulates Na/K-At Pasesignaling And Salt Sensitivity: A Review And A Hypothesis, Preeya Shah Phd, Rebecca Martin, Yanling Yan, Joseph I. Shapiro Md, Jiang Liu

Biochemistry and Microbiology

Na/K-ATPase signaling has been implicated in different physiological and pathophysiological conditions. Accumulating evidence indicates that oxidative stress not only regulates the Na/K-ATPase enzymatic activity, but also regulates its signaling and other functions. While cardiotonic steroids (CTS)-induced increase in reactive oxygen species (ROS) generation is an intermediate step in CTS-mediated Na/K-ATPase signaling, increase in ROS alone also stimulates Na/K-ATPase signaling. Based on literature and our observations, we hypothesize that ROS have biphasic effects on Na/K-ATPase signaling, transcellular sodium transport, and urinary sodium excretion. Oxidative modulation, in particular site specific carbonylation of the Na/K-ATPase α1 subunit, is a critical step in proximal …

The Trade-Off Between Dietary Salt And Cardiovascular Disease; A Role For Na/K-Atpase Signaling?, Joe X. Xie, Anna Pearl Shapiro, Joseph I. Shapiro Md

Biochemistry and Microbiology

It has been postulated for some time that endogenous digitalis-like substances, also called cardiotonic steroids (CTS), exist, and that these substances are involved in sodium handling. Within the past 20 years, these substances have been unequivocally identified and measurements of circulating and tissue concentrations have been made. More recently, it has been identified that CTS also mediate signal transduction through the Na/K-ATPase, and consequently been implicated in profibrotic pathways. This review will discuss the mechanism of CTS in renal sodium handling and a potential “trade-off” effect from their role in inducing tissue fibrosis.