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Updated: Feb 25, 2026
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Author Spotlight: Exploring Cellular Zinc Regulation Through ZnT1 Functionality
Published on: June 2, 2023
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Functional Transport Properties of Human Zinc Transporter 1: Kinetics and pH-Dependency
Yuma Yoshioka1, Takaaki Miyaji1,2
1Department of Molecular Membrane Biology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
Biological & Pharmaceutical Bulletin
|February 23, 2026
Summary
Zinc transporter 1 (ZnT1) exports zinc ions (Zn2+) from cells. This study reveals ZnT1 functions with high affinity and can transport Zn2+ even without a pH gradient, clarifying its transport mechanisms.
Area of Science:
- Cellular Biology
- Biochemistry
- Physiology
Background:
- Intracellular zinc homeostasis is crucial for cellular functions.
- Zinc transporter 1 (ZnT1) regulates zinc export but its transport properties are debated.
- Understanding ZnT1 kinetics and driving forces is vital for cellular zinc regulation.
Purpose of the Study:
- To elucidate the functional transport properties, kinetics, and driving forces of Zinc transporter 1 (ZnT1).
- To investigate ZnT1's zinc (Zn2+) transport mechanisms using a cell-free proteoliposome system.
- To clarify the role of pH and calcium gradients in ZnT1-mediated Zn2+ transport.
Main Methods:
- Established a cell-free proteoliposome assay system for ZnT1 studies.
- Analyzed Zn2+ transport kinetics (Km, Vmax) under various pH conditions.
- Investigated the influence of pH and calcium (Ca2+) gradients on ZnT1 activity.
Main Results:
- ZnT1 exhibits high-affinity Zn2+ transport in both pH-dependent and pH-independent manners.
- ZnT1 demonstrates biphasic kinetics for Zn2+ transport.
- ZnT1 transports Zn2+ effectively even without a pH gradient and Ca2+ does not enhance transport.
- Optimal ZnT1 activity observed at specific intracellular pH, with reduced activity at alkaline extracellular pH.
Conclusions:
- ZnT1 protein actively transports Zn2+ with high affinity and biphasic kinetics.
- ZnT1 can export excess intracellular Zn2+ independent of pH or Ca2+ gradients.
- ZnT1 plays a significant role in maintaining cellular zinc homeostasis through efficient Zn2+ export.
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