1. Cul3 neddylation is crucial for gradual lipid droplet formation during adipogenesis
- Author
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Thilo Kähne, Michael Naumann, Dawadschargal Dubiel, Wolfgang Dubiel, and Willem Bintig
- Subjects
0301 basic medicine ,Proteasome Endopeptidase Complex ,RHOA ,NEDD8 Protein ,Ubiquitin-Protein Ligases ,Cellular differentiation ,Primary Cell Culture ,Mice ,03 medical and health sciences ,Ubiquitin ,Downregulation and upregulation ,Cell Line, Tumor ,Lipid droplet ,Adipocytes ,Animals ,Humans ,Ubiquitins ,Molecular Biology ,Adipogenesis ,biology ,Ubiquitination ,Cell Differentiation ,Lipid Droplets ,Cell Biology ,Fibroblasts ,Cullin Proteins ,Cell biology ,030104 developmental biology ,rab GTP-Binding Proteins ,Proteolysis ,biology.protein ,Neddylation ,rhoA GTP-Binding Protein ,Protein Processing, Post-Translational ,Cullin ,Signal Transduction - Abstract
Cullin 3 (Cul3) belongs to the family of cullins (Cul1–7) providing the scaffold for cullin-RING ubiquitin (Ub) ligases (CRLs), which are activated by neddylation and represent essential E3 ligases of the Ub proteasome system. During adipogenic differentiation neddylated Cul3 accumulates in LiSa-2 preadipocytes. Downregulation of Cul3 and inhibition of neddylation by MLN4924 blocks the formation of lipid droplets (LDs), the lipid storage organelles and markers of adipogenesis. Neddylation of Cul3 coincides with an increase of Rab18, a GTPase associated with LDs. Immunoprecipitation and confocal fluorescence microscopy revealed physical association of Cul3 and Rab18 at the membrane of LDs. RhoA, a suppressor of adipogenesis decreased during differentiation. Our results in LiSa-2 cells, but also mouse embryonic fibroblasts revealed a connection between Cul3, Rab18 and RhoA. Downregulation of Cul3 led to a marked increase in RhoA protein expression after 6 days of LiSa-2 cell differentiation, suggesting that Cul3 is involved in the regulation of RhoA stability.
- Published
- 2017
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