Journal: Nature communications
Article Title: p38γ and δ promote heart hypertrophy by targeting the mTOR-inhibitory protein DEPTOR for degradation.
doi: 10.1038/ncomms10477
Figure Lengend Snippet: Figure 6 | p38c/d control cell size and protein synthesis through DEPTOR levels. (a) p38g/d / MEFs present altered serum-induced DEPTOR degradation. WT and p38g/d / MEFs were serum-starved for 30 h, followed by serum addition. Cells were collected at successive time points for immunoblotting with the indicated antibodies. (b) p38g/d / MEFs are of below-normal size. Cell size was measured by flow cytometry (forward scatter). Right: representative histogram. Left: quantification graph of the forward scatter mean fluourescence intensity (FSC-A MFI) relative to WT. Data are means±s.e.m. ***Po0.001 (t-test). (c) p38g/d / MEFs have downregulated protein synthesis. SUnSET was performed by pulsing 10 min 10 mg ml 1 puromycin and chasing for 1 h before FACS analysis with anti-puromycin 12D10 antibody and anti-mouse IgG conjugated with PE. Data are means±s.e.m. ***Po0.001 (t-test). (d) p38g/d-induced DEPTOR degradation by the proteasome. HELA cells co-transfected with active p38g and p38d mutants were serum-starved for 30 h. Cells were treated with MG132 (10 mM) or vehicle together with 10 mM cycloheximide (CHX) for 9 h, and were analysed by immunoblotting with the indicated antibodies. (e) Silencing DEPTOR in p38g/d / MEF cells restores mTOR signalling. MEFs were singly or doubly infected with two different DEPTOR lentiviral shRNA constructs for 24 h. Uninfected cells were eliminated by selection with 3 mg ml 1 puromycin for 1 week. The resulting cell lines were then serum-starved for 24 h before collecting. Equal amounts of whole-cell lysates were immunoblotted with the indicated antibodies. (f) Silencing of DEPTOR in p38g/d / MEFs increases protein synthesis. MEFs were infected as in e. In the resulting cell lines, the protein concentration per cell was measured by SUnSET assay, performed as in b. Data are means±s.e.m. **Po0.01; ***Po0.001 (one-way analysis of variance coupled to Bonferroni post tests).
Article Snippet: The plasmids used in the different experiments were pRK5 myc Rat mTOR (plasmid #1861, Addgene); pRK5 FLAG human DEPTOR (plasmid #21334, Addgene); pRK5 FLAG human DEPTOR (13xS/T-A; plasmid #21702, Addgene); pRK5 FLAG DEPTOR (PDZ domain; plasmid #21701, Addgene); pRK5 FLAG DEPTOR (DEP domains; plasmid #21700, Addgene); pcDNA3-myc3-CUL1 (plasmid #19896, Addgene); pcDNA3-myc3-bTrCP (plasmid #20718, Addgene); HA-Ubiquitin (plasmid #18712); pcDNA3 HA human p38g and pcDNA3 HA human p38d, kindly provided by Roger Davis (University of Massachusetts Medical School, Worcester, USA); and pCEFL Flag p38gD129A and pCMV Flag p38dF324S, kindly provided by David Engelberg (The Hebrew University of Jerusalem, Israel).
Techniques: Control, Western Blot, Cytometry, Transfection, Infection, shRNA, Construct, Selection, Protein Concentration