Functional characterization of ACDP2 (ancient conserved domain protein), a divalent metal transporter
| Autor: | Angela Goytain, Gary A. Quamme |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Male
Kidney Cortex Cations Divalent Physiology Xenopus Molecular Sequence Data Protein domain Divalent Mice Xenopus laevis Protein structure Cations Genetics Animals Magnesium Tissue Distribution Amino Acid Sequence RNA Messenger Cation Transport Proteins Peptide sequence Gene chemistry.chemical_classification biology Reverse Transcriptase Polymerase Chain Reaction Membrane Transport Proteins RNA Biological Transport Epithelial Cells Protein Structure Tertiary Up-Regulation Transport protein Electrophysiology Kinetics Kidney Tubules Biochemistry chemistry Oocytes biology.protein Protein A Plasmids |
| Zdroj: | Physiological Genomics. 22:382-389 |
| ISSN: | 1531-2267 1094-8341 |
| DOI: | 10.1152/physiolgenomics.00058.2005 |
| Popis: | We have begun to identify and characterize genes that are differentially expressed with low magnesium. One of these sequences conformed to the ancient conserved domain protein, ACDP2. Real-time RT-PCR of mRNA isolated from distal epithelial cells cultured in low-magnesium media relative to normal media and in kidney cortex of mice maintained on low-magnesium diets compared with those animals consuming normal diets confirmed that the ACDP2 transcript is responsive to magnesium. Mouse ACDP2 was cloned from mouse distal convoluted tubule cells, expressed in Xenopus laevis oocytes, and studied with two-electrode voltage-clamp studies. When expressed in oocytes, ACDP2 mediates saturable Mg2+uptake with a Michaelis constant of 0.56 ± 0.05 mM. Transport of Mg2+by ACDP2 is rheogenic, is voltage-dependent, and is not coupled to Na+or Cl−ions. Expressed ACDP2 transports a range of divalent cations: Mg2+, Co2+, Mn2+, Sr2+, Ba2+, Cu2+, and Fe2+; accordingly, it is a divalent cation transporter with wide substrate selectivity. The cations Ca2+, Cd2+, Zn2+, and Ni2+did not induce currents, and only Zn2+effectively inhibited transport. The ACDP2 transcript is abundantly present in kidney, brain, and heart with lower amounts in liver, small intestine, and colon. Moreover, ACDP2 mRNA is upregulated with magnesium deficiency, particularly in the distal convoluted tubule cells, kidney, heart, and brain. These studies suggest that ACDP2 may provide a regulated transporter for Mg2+and other divalent cations in epithelial cells. |
| Databáze: | OpenAIRE |
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