Drosophila melanogaster lipins are tissue-regulated and developmentally regulated and present specific subcellular distributions.
Lipins constitute a novel family of Mg(2+)-dependent phosphatidate phosphatases that catalyze the dephosphorylation of phosphatidic acid to yield diacylglycerol, an important intermediate in lipid metabolism and cell signaling. Whereas a single lipin is detected in less complex organisms, in mammals there are distinct lipin isoforms and paralogs that are differentially expressed among tissues. Compatible with organism tissue complexity, we show that the single Drosophila Lpin1 ortholog (CG8709, here named DmLpin) expresses at least three isoforms (DmLpinA, DmLpinK and DmLpinJ) in a temporal and spatially regulated manner. The highest levels of lipin in the fat body, where DmLpinA and DmLpinK are expressed, correlate with the highest levels of triacylglycerol (TAG) measured in this tissue. DmLpinK is the most abundant isoform in the central nervous system, where TAG levels are significantly lower than in the fat body. In the testis, where TAG levels are even lower, DmLpinJ is the predominant isoform. Together, these data suggest that DmLpinA might be the isoform that is mainly involved in TAG production, and that DmLpinK and DmLpinJ could perform other cellular functions. In addition, we demonstrate by immunofluorescence that lipins are most strongly labeled in the perinuclear region of the fat body and ventral ganglion cells. In visceral muscles of the larval midgut and adult testis, lipins present a sarcomeric distribution. In the ovary chamber, the lipin signal is concentrated in the internal rim of the ring canal. These specific subcellular localizations of the Drosophila lipins provide the basis for future investigations on putative novel cellular functions of this protein family.
Department of Cellular and Molecular Biology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Valeria
V
Valente
Rafaela Martins
RM
Maia
Murilo Carlos Bizam
MC
Vianna
Maria Luisa
ML
Paçó-Larson
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D029721:Drosophila Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000201:enzymology* / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D020033:Protein Isoforms / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000201:enzymology*; D014018:Tissue Distribution; D014280:Triglycerides / Q000378:metabolism
D029721:Drosophila Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D014280:Triglycerides; D010744:Phosphoric Monoester Hydrolases