Fig 5. CnB1 regulates TTP stability through proteasomal mediation.
A. qRT-PCR analysis of TTP expression level from the dorsal epidermis of two wild-type (wt) and two CnB1-/- (KO) mice 24 hr after treatment with UVB (+) or sham-irradiation (-) as control. B. Ad-GFP- or Ad-Cre-infected CnB1flox/flox MKCs were treated with UVB (+) or sham-irradiated (-). Four hours after treatment, cells were analyzed for TTP mRNA level by qRT-PCR. C,D. HKCs were transfected with siRNAs of scramble RNA (siCtrl), calcineurin B1(siCnB1), NFATc1(siC1) or NFATc4 (siC4) or were treated with DMSO, CsA, Veet or Vivit. 48 hr after treatment, cells were analyzed for TTP mRNA level by qRT-PCR. A-D: Normalized to 36B4 gene, *p<0.05, **p<0.01, ***p<0.001; n = 3. E. Ad-GFP- or Ad-Cre-infected CnB1flox/flox MKCs, UVB-irradiated as in B, were incubated with puromycin (PURO) or DMSO (ctrl). Cells were then collected at the indicated times and analyzed by immuoblot for TTP (tubulin as loading control). F. Ad-GFP- or Ad-Cre-infected CnB1-loxP MKCs were treated with UVB as in B, in the presence of epoxomicin 1μM (EPOX) or DMSO at the indicated times. Cells were then analyzed by immunoblot for TTP, tubulin as a loading control. G. HKCs with over-expression of TTP (TTP-OE) with treated either with CsA with or without MG132 were collected at indicated times for analysis of TTP protein level. H. qRT-PCR analysis of TTP mRNA level at indicated time points in HKCs treated with CsA with or without MG132.