Lipid composition of cAMP-dependent protein kinase mutants of Aspergillus niger.
Lipid composition of cAMP-dependent protein kinase (PKA) Aspergillus niger mutants with overexpressed or deleted genes for either regulatory and/or the catalytic subunit of PKA was analyzed. Disruption of the gene encoding the PKA regulatory subunit resulted in 20% less total lipids, 30% less neutral lipids, four times more glycolipids and two-fold higher triacylglycerol lipase activity compared to the control strain. Concomitantly a five-fold decrease in phosphatidylcholine, accompanied with 1.5-, 1.8- and 2.8-fold increases in phosphatidylethanolamine, lysophosphatidylethanolamine and phosphatidylinositol, was determined, respectively. The lack of PKA activity, due to the disruption of a gene encoding the PKA catalytic subunit, resulted in a 1.6-times increase in total lipids with two times more neutral lipids associated with lower triacylglycerol lipase activity and a decrease in phospholipids. The mutants with unrestricted PKA activity synthesized twice as much citric acid as the control strain and three times more than strains lacking PKA activity. The results indicate the involvement of cAMP-mediated PKA activity in regulation of lipid biosynthesis as well as citric acid synthesis.
Jernejc
Katarina
K
Laboratory of Biotechnology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. katarina.jernejc@ki.si
Bencina
Mojca
M
D001234:Aspergillus niger / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020134:Catalytic Domain / Q000235:genetics; D002845:Chromatography; D019343:Citric Acid / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D017353:Gene Deletion; D015870:Gene Expression; D006017:Glycolipids / Q000032:analysis; D008049:Lipase / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis*; D009154:Mutation; D025282:Mycelium / Q000737:chemistry*; D010743:Phospholipids / Q000032:analysis; D021122:Protein Subunits / Q000235:genetics
D005227:Fatty Acids; D006017:Glycolipids; D008055:Lipids; D010743:Phospholipids; D021122:Protein Subunits; D019343:Citric Acid; D017868:Cyclic AMP-Dependent Protein Kinases; D008049:Lipase