scholarly journals Growth Hormone Regulates Phosphorylation and Function of CCAAT/Enhancer-binding Protein β by Modulating Akt and Glycogen Synthase Kinase-3

2001 ◽  
Vol 276 (22) ◽  
pp. 19664-19671 ◽  
Author(s):  
Graciela Piwien-Pilipuk ◽  
David Van Mater ◽  
Sarah E. Ross ◽  
Ormond A. MacDougald ◽  
Jessica Schwartz
Keyword(s):  
Growth Hormone ◽  
Glycogen Synthase ◽  
Binding Protein ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
And Function

scholarly journals Natural Functions of PLIN2 Mediating Wnt/LiCl Signaling and Glycogen Synthase Kinase 3 (GSK3)/GSK3 Substrate-Related Effects Are Modulated by Lipid

2015 ◽  
Vol 36 (3) ◽  
pp. 421-437 ◽  
Author(s):  
Xunxian Liu ◽  
Xinyue Lu ◽  
Kaimei Song ◽  
Marc R. Blackman
Keyword(s):  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Insulin Receptor Substrate ◽  
T Cell Factor ◽  
Mediated Effects ◽  
C Terminus ◽  
High Lipid ◽  
Enhancer Binding Protein ◽  
Interfering Rna

Belonging to the PLIN family, PLIN2 associates with lipid storage droplets (LSDs), but other functions of PLIN2 remain unclear. Here, we suggest that PLIN2 mediates Wnt signaling because PLIN2 small interfering RNA (siRNA) suppresses activation of Wnt/coreceptor pathways. The mediation in the Wnt/Frizzled pathway seems to occur from Dishevelleds to axin/glycogen synthase kinase 3(GSK3)/β-catenin complexes (AGβC) as Wnt decreases Dishevelled/PLIN2 but increases AGβC/PLIN2 associations. Augmenting cellular LSDs that affect PLIN2 associations with these proteins, oleic acid (OA) treatment inhibits Wnt-increased AGβC/PLIN2 associations and β-catenin T-cell factor signaling (β-CTS). Revealing that PLIN2 is a GSK3-associated protein, the study explored PLIN2-mediated effects on GSK3/GSK3 substrates. PLIN2 siRNA reduces inhibitory GSK3 levels and lithium chloride (LiCl)-upregulated β-catenin or CCAAT/enhancer binding protein α (c/EBPα) expression. OA treatment decreases LiCl-increased c/EBPα via PLIN2-c/EBPα dissociation. In addition to PLIN2 overexpression increasing β-CTS, PLIN2 depletion or overexpression drops or adds expression of GSK3 substrates, such as β-catenin, c/EBPα,c-Myc, cyclin D1, and insulin receptor substrate 1, and cell growth/survival. PLIN2 N or C terminus overexpression that is associated with higher levels of the substrates suggests that those substrates bind to specific regions of PLIN2. Mimicking the possible high lipid concentrations in cells in the human body under conditions of hyperlipidemia/obesity, OA-treated cells gain or reduce GSK3 substrate expression in parallel with a decrease (a Wnt-like effect) or increase in GSK3 activity, likely regulated by GSK3/PLIN2/GSK3 substrate associations.

scholarly journals Endogenous CCAAT/Enhancer Binding Protein β and p300 Are Both Regulated by Growth Hormone to Mediate Transcriptional Activation

2005 ◽  
Vol 19 (8) ◽  
pp. 2175-2186 ◽  
Author(s):  
Tracy Xiao Cui ◽  
Graciela Piwien-Pilipuk ◽  
Jeffrey S. Huo ◽  
Julianne Kaplani ◽  
Roland Kwok ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein
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