title: GABA-shunt enzymes activity in GH3 cells with reduced level of PMCA2 or PMCA3 isoform.
abstract: GABA (γ-aminobutyric acid) is important neurotransmitter and regulator of endocrine functions. Its metabolism involves three enzymes: glutamate decarboxylase (GAD65 and GAD67), GABA aminotransferase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH). As many cellular processes GABA turnover can depend on calcium homeostasis, which is maintained by plasma membrane calcium ATPases (PMCAs). In excitable cells PMCA2 and PMCA3 isoforms are particularly important. In this study we focused on GABA-metabolizing enzymes expression and activity in rat anterior pituitary GH3 cells with suppressed expression of PMCA2 or PMCA3. We observed that PMCA3-reduced cells have increased GAD65 expression. Suppression of PMCA2 caused a decrease in total GAD and GABA-T activity. These results indicate that PMCA2 and PMCA3 presence may be an important regulatory factor in GABA metabolism. Results suggest that PMCA2 and PMCA3 function is rather related to regulation of GABA synthesis and degradation than supplying cells with metabolites, which can be potentially energetic source.
authors.affiliation: Department of Molecular Neurochemistry, Medical University of Lodz, Poland. antoni.kowalski@umed.lodz.pl
authors.forename: Antoni
authors.initials: A
authors.lastname: Kowalski
authors.forename: Ludmiła
authors.initials: L
authors.lastname: Zylińska
authors.forename: Tomasz
authors.initials: T
authors.lastname: Boczek
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Rębas
mesh_terms: D000818:Animals; D002460:Cell Line; D005968:Glutamate Decarboxylase / Q000096:biosynthesis / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
chemical_list: D007527:Isoenzymes; D005680:gamma-Aminobutyric Acid; D053499:Plasma Membrane Calcium-Transporting ATPases; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2