Structure and function of the human Na+/H+ exchanger isoform 1.
Grant Kemp1, Howard Young, Larry Fliegel
1Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada.
Channels (Austin, Tex.)
|November 13, 2008
Summary
Sodium proton exchangers (NHEs) are vital membrane transporters. This review covers human NHE roles in physiology and disease, focusing on NHE1 structure and a new Na+/Li+ exchanger.
Area of Science:
- Biochemistry
- Molecular Biology
- Physiology
Background:
- Sodium proton exchangers (NHEs) are polytopic membrane proteins facilitating proton/sodium ion exchange across cellular membranes.
- NHEs are crucial for salt tolerance in various organisms and play significant roles in human physiology, including pH regulation, cell growth, and differentiation.
- Dysfunctional NHEs are implicated in pathological conditions such as heart disease.
Purpose of the Study:
- To provide an overview of human NHE physiological and pathological roles, and their cellular/tissue distribution.
- To summarize current knowledge on the structure and function of the exemplar NHE1 isoform, addressing recent topological discrepancies.
- To discuss a newly identified Na+/Li+ exchanger, its predicted topology, and potential disease relevance.
Main Methods:
- Literature review of existing studies on NHE structure, function, and physiological/pathological roles.
- Analysis of reported data regarding NHE1 topology and functional discrepancies.
- Review of predictions and potential roles for the Na+/Li+ exchanger.
Main Results:
- Human NHEs have diverse physiological functions, with NHE1 being prominent in intracellular pH regulation.
- Recent studies present conflicting data on NHE1 topology, necessitating further investigation.
- A novel Na+/Li+ exchanger has been identified, with its topology and disease associations under preliminary investigation.
Conclusions:
- Human NHEs, particularly NHE1, are critical for cellular homeostasis and implicated in various diseases.
- Clarifying NHE1 topology is essential for understanding its function and therapeutic targeting.
- The newly discovered Na+/Li+ exchanger represents a potential new avenue for research in ion transport and disease.
More Related Videos
11:51Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters
Published on: February 3, 2018
12:48Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays
Published on: February 19, 2013
Related Concept Videos
01:29Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...
01:47Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they...
01:17Reabsorption and Secretion in the Loop of Henle
The thick ascending limb of the nephron loop has Na+–K+–2Cl− symporters in the apical membranes of its cells. These symporters simultaneously reclaim one sodium ion, one potassium ion, and two chloride ions from the tubular fluid. Sodium ions are actively transported into the interstitial fluid at the base and sides of the cell, diffusing into the vasa recta. Chloride ions move through leakage channels in the basolateral membrane into the interstitial fluid and then into the vasa recta.
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:55Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...