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Structure, tissue expression pattern, and function of the amino acid transporter rat PAT2
Zhong Chen1, David J Kennedy, Katherine A Wake
1Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA.
Summary
Researchers identified rat PAT2, a novel proton-coupled amino acid transporter. This pH-dependent transporter shows distinct substrate specificity and limited tissue distribution compared to rat PAT1.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The proton-coupled amino acid transporter (PAT) family plays a crucial role in amino acid transport.
- Understanding the diversity and function of PAT family members is essential for cellular physiology.
Purpose of the Study:
- To isolate and characterize the second member of the rat PAT family, designated rat PAT2.
- To determine the tissue distribution and functional properties of rat PAT2.
Main Methods:
- Isolation of rat PAT2 cDNA from a rat lung cDNA library.
- Gene localization to rat chromosome 10q22.
- Functional expression studies in mammalian cells and Xenopus laevis oocytes.
- Analysis of substrate specificity and kinetic properties.
Main Results:
- Rat PAT2 cDNA codes for a 481-amino acid protein with 72% identity to rat PAT1.
- mRNA expression is highest in lung and spleen, with lower levels in other tissues.
- Rat PAT2 mediates pH-dependent, Na(+)-independent uptake of glycine, proline, and MeAIB.
- PAT2 exhibits higher affinity for glycine compared to PAT1.
Conclusions:
- Rat PAT2 is a novel amino acid transporter with a limited tissue distribution.
- PAT2 possesses distinct substrate specificity and kinetic properties compared to PAT1.
- These findings contribute to the understanding of amino acid transport mechanisms.