1. Suppression of PPARγ through MKRN1-mediated ubiquitination and degradation prevents adipocyte differentiation
- Author
-
Hwang Ka, Eun-Woo Lee, Jongbum Seo, Jin Hong Kim, Jang Ws, Jaewhan Song, Kye Won Park, and Soyeon Shin
- Subjects
Cellular differentiation ,Peroxisome proliferator-activated receptor ,Nerve Tissue Proteins ,Mice ,chemistry.chemical_compound ,Ubiquitin ,3T3-L1 Cells ,Adipocyte ,Adipocytes ,Animals ,Humans ,RNA, Messenger ,RNA, Small Interfering ,Molecular Biology ,Cells, Cultured ,chemistry.chemical_classification ,Original Paper ,Adipogenesis ,biology ,Lysine ,HEK 293 cells ,Ubiquitination ,Cell Differentiation ,Cell Biology ,Molecular biology ,Cell biology ,Ubiquitin ligase ,Mice, Inbred C57BL ,PPAR gamma ,HEK293 Cells ,Ribonucleoproteins ,chemistry ,Nuclear receptor ,biology.protein ,RNA Interference - Abstract
The central regulator of adipogenesis, PPARγ, is a nuclear receptor that is linked to obesity and metabolic diseases. Here we report that MKRN1 is an E3 ligase of PPARγ that induces its ubiquitination, followed by proteasome-dependent degradation. Furthermore, we identified two lysine sites at 184 and 185 that appear to be targeted for ubiquitination by MKRN1. Stable overexpression of MKRN1 reduced PPARγ protein levels and suppressed adipocyte differentiation in 3T3-L1 and C3H10T1/2 cells. In contrast, MKRN1 depletion stimulated adipocyte differentiation in these cells. Finally, MKRN1 knockout MEFs showed an increased capacity for adipocyte differentiation compared with wild-type MEFs, with a concomitant increase of PPARγ and adipogenic markers. Together, these data indicate that MKRN1 is an elusive PPARγ E3 ligase that targets PPARγ for proteasomal degradation by ubiquitin-dependent pathways, and further depict MKRN1 as a novel target for diseases involving PPARγ.
- Published
- 2013