Project Details
Projekt
Function of perilipin 3 in lipid droplet heterogeneity and metabolism
Applicant
Professor Dr. Joachim Füllekrug
Subject Area
Cell Biology
Biochemistry
Biochemistry
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 538651361
Perilipin (PLIN1-5) family proteins are abundantly and constitutively present on all vertebrate lipid droplets (LDs). However, especially the functional relevance of the ubiquitous perilipin 3 (PLIN3) has remained elusive. PLIN3 is not equally distributed on LDs but preferentially localizes to smaller sized LD subpopulations assumed to reflect recent biogenesis. PLIN3-deficient U2OS cells showed an unexpected reduction of fatty acid (FA) uptake and metabolism, correlating with decreased transcription and activity of the key FA activating enzyme ACSL3. This was specific for PLIN3, as knockout of the only other perilipin expressed in the U2OS model (PLIN2) did not show similar changes. The working hypothesis of this proposal is that PLIN3 acts as a subpopulation specific lipid droplet sensor and is linked to the regulation of lipid metabolism. The corresponding specific objectives of the work program are: 1. Analysis of PLIN3-dependent LD heterogeneity. PLIN3-specific LD subpopulations will be characterized by microscopy in relation to nutrient fluctuations. The molecular basis of heterogeneity will be investigated by dedicated screening for PLIN3-protein/lipid interactions. 2. Characterization of fatty acid metabolism in PLIN3-KO cells. Dysregulated lipid metabolism will be followed by chromatography, isotope labeling, mass spectrometry and oxygen consumption to identify targets linked to PLIN3 deficiency. 3. Analysis of posttranslational modifications of PLIN3. Identification of reversible posttranslational modifications of PLIN3 correlating to LD heterogeneity and metabolic regulation will be followed by testing point mutated, inactive PLIN3 variants for rescue of PLIN3-KO phenotypes. 4. Elucidating the mediators of PLIN3-dependent metabolic rewiring. Transcriptome analysis of PLIN3-KO cells together with results from 1.-3. will allow to identify and characterize transcription factors connecting PLIN3 to the lipid metabolic network. Overall, the anticipated key result is the identification of regulatory lipid metabolic networks uniquely mediated by the perilipin family protein PLIN3. This will allow insight into the molecular regulation of lipid storage by LD associated structural proteins, with implications for widespread metabolic diseases.
DFG Programme
Research Units
