Aromatic amino acid transporter AAT-9 of Caenorhabditis elegans localizes to neurons and muscle cells
| Autor: | Attila Stetak, Charles B. Shoemaker, Susan J. Stasiuk, Alex Hajnal, François Verrey, Patrick J. Skelly, Ian C. Forster, Andrea Bacconi, Emilija Veljkovic |
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| Přispěvatelé: | University of Zurich, Verrey, F |
| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Time Factors
1303 Biochemistry Amino Acid Transport Systems Aromatic amino acid transport Biochemistry Protein Structure Secondary RNA Complementary 10052 Institute of Physiology Levodopa 1307 Cell Biology chemistry.chemical_compound Xenopus laevis Protein structure Aromatic amino acids Disulfides Transgenes Cloning Molecular Promoter Regions Genetic Caenorhabditis elegans Phylogeny chemistry.chemical_classification Neurons Muscles Immunohistochemistry 10124 Institute of Molecular Life Sciences Amino acid Electrophysiology Phenotype Plasmids congenital hereditary and neonatal diseases and abnormalities DNA Complementary Protein subunit Phenylalanine Green Fluorescent Proteins Biology Amino Acids Aromatic 1312 Molecular Biology Animals Humans Cysteine Gene Silencing Molecular Biology Ions Cell Membrane Biological Transport Cell Biology biology.organism_classification Protein Structure Tertiary Kinetics chemistry Microscopy Fluorescence Oocytes 570 Life sciences biology Glycoprotein |
| DOI: | 10.5167/uzh-362 |
| Popis: | The Caenorhabditis elegans genome encodes nine homologues of mammalian glycoprotein-associated amino acid transporters. Two of these C. elegans proteins (AAT-1 and AAT-3) have been shown to function as catalytic subunits (light chains) of heteromeric amino acid transporters. These proteins need to associate with a glycoprotein heavy chain subunit (ATG-2) to reach the cell surface in a manner similar to that of their mammalian homologues. AAT-1 and AAT-3 contain a cysteine residue in the second putative extracellular loop through which a disulfide bridge can form with a heavy chain. In contrast, six C. elegans members of this family (AAT-4 to AAT-9) lack such a cysteine residue. We show here that one of these transporter proteins, AAT-9, reaches the cell surface in Xenopus oocytes without an exogenous heavy chain and that it functions as an exchanger of aromatic amino acids. Two-electrode voltage clamp experiments demonstrate that AAT-9 displays a substrate-activated conductance. Immunofluorescence shows that it is expressed close to the pharyngeal bulbs within C. elegans neurons. The selective expression of an aat-9 promoter-green fluorescent protein construct in several neurons of this region and in wall muscle cells around the mouth supports and extends these localization data. Taken together, the results show that AAT-9 is expressed in excitable cells of the nematode head and pharynx in which it may provide a pathway for aromatic amino acid transport. |
| Databáze: | OpenAIRE |
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