For instance, cell co-stimulation with insulin and low levels of EGF, both being weak activators of ERK, induces synergic ERK activation in human embryonic kidney (HEK 293 cells [ 27].
DOI: http://dx.doi.org/10.7554/eLife.01340.016 Despite binding to the mSmo CRD, 20(R -yne and 20-keto-yne weR -ynek andivators of signaling in the absence of Shh, reinforcing the importance of stereochemistry at position 20 for Smo activation.
That is, ERFs from subclass C are strong activators and those belonging to subclasses A, B and E are weak activators, whereas members of subclass F are clear repressors.
Among autoantibodies to BRAF that activated MEK1 phosphorylation, 10/13 were weak activators (1 < ratio < 1.5) and 3/13 were strong activators (ratio > 1.5).
NeuroD1 is considered to be a weak activator of transcription, but is known to cooperate with other transcription factors, including Rreb1 and Sp1[ 26] 26], in the stimulation of gene expression.
These components can be involved in both genomic and nongenomic pathways of estrogen action, but have recently been shown to be very potent when acting via the non-genomic pathway (Wozniak et al. 2005), although they are very weak activators of the genomic pathway.
SREBPs are known to be weak transcriptional activators and require the presence of additional transcription factors like Sp1 and NF-Y to elicit maximal activation [ 2, 37, 38].
We propose that AhR-signaling may be a weak activator of p65-signaling that suppresses p65-activity induced by strong activators of NF-κB, but that its anti-inflammatory properties also are due to interference with additional pathways.
This is particularly surprising because THR0921 is a weak activator of PPARγ compared to rosiglitazone and has less adipogenic activity.
SCH 351448 is a novel ionophoric compound and is a weak activator of low density lipoprotein receptor (LDL-R) promoter with an IC50 of 25 μM.
