Dataset Information

Systematic genome perturbation reveals coordination of lipid droplets and metabolic gene regulation

ABSTRACT: Lipid droplets (LDs) store lipids for metabolic eneergy and are central to cellular lipid homeostasis. The mechanisms coordinating lipid storage in LDs with cellular metabolism are unclear but relevant to obesity-related diseases. Here we utilized genome-wide screening to identify genes that modulate lipid storage in human macrophages, a cell type relevant to metabolic diseases. Among ~550 genes regulating lipid storage, we identify MLX, a basic helix-loop-helix leucine-zipper transcription factor that regulates multiple metabolic processes. We show that MLX and family members MLXIP/MondoA and MLXIPL/ChREBP bind LDs via C-terminal amphipathic helices. When LDs increase in cells, LD binding of MLX, MLXIP/MondoA, and MLXIPL/ChREBP reduces their transcriptional activity, whereas the absence of LDs results in hyperactivation. Our findings uncover an unexpected component to a lipid storage response, in which binding of MLX transcription factors to the LD surface modulates their activity, adjusting the expression of metabolic genes to lipid storage levels.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture, Macrophage

SUBMITTER: Zon Weng Lai

LAB HEAD: Tobias Walther

PROVIDER: PXD012640 | Pride | 2021-09-08

REPOSITORIES: Pride

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Publications

Partitioning of MLX-Family Transcription Factors to Lipid Droplets Regulates Metabolic Gene Expression.

Mejhert Niklas N Kuruvilla Leena L Gabriel Katlyn R KR Elliott Shane D SD Guie Marie-Aude MA Wang Huajin H Lai Zon Weng ZW Lane Elizabeth A EA Christiano Romain R Danial Nika N NN Farese Robert V RV Walther Tobias C TC

Molecular cell 20200204 6

Lipid droplets (LDs) store lipids for energy and are central to cellular lipid homeostasis. The mechanisms coordinating lipid storage in LDs with cellular metabolism are unclear but relevant to obesity-related diseases. Here we utilized genome-wide screening to identify genes that modulate lipid storage in macrophages, a cell type involved in metabolic diseases. Among ∼550 identified screen hits is MLX, a basic helix-loop-helix leucine-zipper transcription factor that regulates metabolic process ...[more]

PMID: 32023484

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Project description:The regulation of organismic lipid storage amounts is a central goal of all organisms. Proteins associated with the dedicated lipid storage organelles, the so-called lipid droplets (LDs), are instrumental to this regulation. LD proteomes of diverse organisms have been characterized by mass spectrometry. Yet, the functional characterization of most of these proteins is still lagging behind. Moreover, knowledge of interactions among LD-associated proteins is sparse and mostly limited to proteins involved in mammalian lipolysis regulation. This process crucially depends on an orchestrated set of protein-protein interactions which limit the accessibility, and thus remobilization, of the lipid stores. Thus, a better knowledge of the LD-associated protein interactome likely reveals entry points to deeper understand lipid storage regulation on a mechanistic level. Here, we utilize a split-luciferase based protein-protein interaction assay to identify interactions among 46 LD-associated proteins and protein variants of which 40 are Drosophila and 6 mouse proteins. In 1531 complementation tests, we assayed for interactions among 487 luciferase fragment fusion protein pairs (covered by 830 different construct combinations) of which 85 (17.45 %) resulted in a significant luciferase complementation. These results suggest, that a prominent fraction of the LD-associated proteome participates in protein-protein interactions, and provide a basis for further functional studies. Besides confirming previously described interactions, we identified several new protein interaction pairs. Of these, we characterize the following three in greater detail: (i) Jabba and CG9186, (ii) Jabba and Histones and (iii) Ubiquitin and CG9186. The interaction among Jabba and Histones is of physiological significance and we provide data suggesting that Jabba alone is sufficient to recruit Histones to LDs. Further, we identified a positively charged amino acid stretch of 16 amino acids within the Jabba protein which is necessary for the Jabba-Histone interaction. CG9186 is an annotated esterase which is involved in lipid storage amount regulation and positioning of LDs. We present data supporting the ubiquitination of at least two lysine residues of CG9186 and demonstrate a role of CG9186 ubiquitination in the induction of LD clusters linked to the overexpression of CG9186.

Dataset Information

Systematic genome perturbation reveals coordination of lipid droplets and metabolic gene regulation

Publications

Partitioning of MLX-Family Transcription Factors to Lipid Droplets Regulates Metabolic Gene Expression.

Similar Datasets

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