Although first described as a mechanism for proteolysis of misfolded or damaged proteins, ubiquitination is now appreciated as an important modification for cellular trafficking and transcriptional activation, as well as for proteasomal- and lysosomal-mediated degradation of signaling intermediates in the regulation of normal cell function.
In sum, these data support Lys ubiquitination as an important modification for phosphorylation of CIITA by ERK1/2.
We have identified a novel ubiquitin (Ub) Lys linkage on CIITA IF3 and further show that Lys ubiquitination is an important modification for changing the subcellular localization and thus activity of the MHC II master regulator.
Regardless of the upstream signaling cascades involved, it is increasingly clear that ER phosphorylation at Ser305 represents an important modification for ligand independence and/or tamoxifen resistance in breast cancer cells.
The majority of differentially expressed genes in KTR mutant were strongly downregulated compared to wild type cells, suggesting that acetylation of p65 at these residues is also an important modification for the expression of the extended NF-κB-dependent gene expression (Fig. 1A).
In this context, the presence of modifications, such as the putative presence of an extra site for N-glycosylation which is reported here for the cultivar Bella de España may represent an important modification in the allergenic capability of the Ole e 1 protein of this pollen, which should be further tested.
In those studies, there is increased DNA-binding activity by EMSA in response to drug treatment, but no change is identified in the level of phosphorylated p65 at the serine 536 residue [11], [12], which has been established as a important modification for NF-κB transcriptional activity [1].
The fact that several kinases can phosphorylate Serine 46 suggests that this may be a very important modification for the regulation and function of p53.
Also, the phosphorothioate chemistry, which was developed by Fritz Eckstein, remains a highly important modification for most of today's ON drugs, since it both confers protection against degradation and aids in the cellular uptake of ONs.
