Arginylation regulates adipogenesis by regulating expression of PPARγ at transcript and protein level

Area of Science:

• Cellular Biology
• Molecular Biology
• Biochemistry

Background:

• Protein arginylation is a post-translational modification impacting protein stability, function, and interactions.
• Disruption of arginylation affects fundamental cellular processes, including proliferation and cell death.

Purpose of the Study:

• To investigate the role of protein arginylation in cell differentiation, specifically focusing on preadipocyte differentiation.
• To elucidate the molecular mechanisms by which arginylation influences adipogenesis.

Main Methods:

• Utilized an in vitro preadipocyte differentiation model.
• Employed inhibition and knockout (KO) of arginyltransferase 1 (ATE1) to study the effects of arginylation loss.
• Analyzed the expression of key adipogenic transcription factors (PPARγ, C/EBPα, C/EBPβ, C/EBPδ) and downstream genes.
• Investigated protein degradation pathways, specifically proteasome-mediated degradation of PPARγ1.

Main Results:

• Inhibition or KO of ATE1 severely hindered preadipocyte differentiation into mature adipocytes.
• Absence of arginylation suppressed the expression of PPARγ and C/EBPα, along with their target adipogenic genes (FABP4, GLUT4, PLN1).
• Arginylation loss led to increased proteasome-mediated degradation of PPARγ1 protein, independent of its transcript levels.
• Inhibition of arginylation in mature adipocytes reduced lipogenesis gene expression and fat accumulation.

Conclusions:

• Arginylation is essential for preadipocyte differentiation and maturation.
• Arginylation influences adipogenesis through transcriptional regulation of PPARγ and C/EBPα, downstream of C/EBPβ and C/EBPδ.
• Arginylation-mediated regulation of PPARγ protein stability plays a significant role in adipogenesis.
• Arginylation is a key factor in maintaining adipose tissue homeostasis.