L-FABP colocalizes with nuclear lipid droplets

LAYERENZA, JUAN PABLO; SISTI, MARTÍN S.; VES LOSADA, ANA

Puerto Madryn

Congreso; XLVI Reunión Anual de SAIB; 2010

SAIB

We have already shown that: 1) L-FABP promotes endonuclear FA mobilization and release to different nuclear and cellular compartments and 2) neutral lipids are organized in discrete non polar domains inside the nuclei (N), Nuclear Lipid Droplets (NLD), which consist of a hydrophobic core of neutral lipids (NL) covered by a monolayer of PL and associated proteins. So, the aim of the present work was to elucidate if L-FABP can mobilize FA to NLD. With this purpose N were incubated in vitro with L-FABP, 20:4n-6 (AA), ATP and / or CoA in different experimental conditions. L-FABP distribution was analyzed by immunofluorescence by fluorescense confocal microscopy. N was stained with DAPI and neutral lipids with BODIPY493/503. L-FABP was internalized in a diffuse pattern of distribution with several intranuclear foci. These foci presented a contact zone (colocalization) with NLD. In particular when N were incubated with L-FABP-AA, NLD were surrounded by L-FABP. In conclusion, these results suggest that L-FABP targets AA directly to NLD. L-FABP foci could represent either alternative soluble AA pools or a nuclear domain that keeps a close relationship with NLD.