Role of Drosophila EDEMs in the degradation of the alpha-1-antitrypsin Z variant.

The synthesis of proteins in the endoplasmic reticulum (ER) that exceeds the protein folding capacity of this organelle is a frequent cause of cellular dysfunction and disease. An example of such a disease is alpha-1-antitrypsin (A1AT) deficiency, caused by destabilizing mutations in this glycoprotein. It is considered that the mutant proteins are recognized in the ER by lectins and are subsequently degraded through the proteasome, leading to a deficiency in this enzyme in the afflicted patients.

Protein kinase A phosphorylates NCoR to enhance its nuclear translocation and repressive function in human prostate cancer cells.

Protein kinase A (PKA) phosphorylates diverse protein substrates to modulate their function. In this study, we found that PKA specifically phosphorylates the RD1 (repression domain 1) domain of nuclear receptor corepressor (NCoR). We demonstrated that the Serine-70 of NCoR is identified the critical amino acid for PKA-dependent NCoR phosphorylation.

N-(4-hydroxyphenyl)retinamide inhibits breast cancer cell invasion through suppressing NF-KB activation and inhibiting matrix metalloproteinase-9 expression.

Synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) has been reported to exhibit anti-invasive and anti-metastatic activities by suppressing the enzymatic activity of matrix metalloproteinase (MMP)-9, but the underlying mechanism remains unclear. Here, we show that 4-HPR blocks the activity of MMP-9 in two ways: by reducing phorbol 12-myristate 13-acetate (PMA)-induced MMP-9 secretion and by suppressing cell invasion through the downregulation of MMP-9 gene transcription in MCF-7 breast cancer cells. 4-HPR inhibits the transcriptional activity of MMP-9 by reducing the DNA-binding activity of NF-κB on the MMP-9 promoter as well as by inhibiting the degradation of IκBα, leading to cytoplasmic accumulation of NF-κB.