Detecting a factor whose activation is a change of address: why an nfkb antibody, the nf-kb antibody spelling beside it and an nfkb p65 antibody or rela antibody report a protein that is present before and after activation and only moves, what an ikba antibody reports by disappearing, how an a20 antibody and a tnfaip3 antibody are the same brake under two names, what a traf2 antibody, a tak1 antibody, an irak4 antibody and a nik antibody mark at successive points in the chain, where a tnfr1 antibody, an ltbr antibody, a tnf antibody, an anti tnf alpha antibody and an il-1 beta antibody sit at the receptor and ligand end, and why fractionation rather than a whole cell lysate is the experiment this pathway actually needs

Designing the experiment

1. Fractionate or image, do not blot whole lysate. Translocation is the activation event. Nuclear and cytoplasmic fractions on the same blot, or imaging of nuclear intensity per cell, are the two readouts that report it. A whole cell lysate averages the answer away.
2. Use inhibitor degradation as the early readout. The inhibitor is destroyed within minutes of stimulation and resynthesised afterwards. Its disappearance is a fast, unambiguous activation signal and needs a tight time course to catch.
3. Validate the fractionation itself. A nuclear fraction contaminated with cytoplasm invalidates the whole experiment. Blot a known nuclear and a known cytoplasmic marker on every fractionation, and show them in the figure.
4. Expect oscillation and design around it. The pathway oscillates rather than switching once, so a single late timepoint can catch a trough. Sample early and often, and report the time course rather than a representative lane.
5. Control with a receptor level block. Blocking at the receptor, or using cells lacking it, distinguishes pathway activation from a general stress response that moves the factor for other reasons.

Location is the measurement

Every useful experiment in this pathway is about where a protein is or whether another one still exists. That makes fractionation quality and imaging quantification the technical crux, rather than antibody sensitivity.

Imaging has an advantage worth noting: it reports the distribution across cells, and this pathway frequently activates in a fraction of a population rather than uniformly. A blot would report that as a modest average change.

The brakes are part of the signal

Negative regulators are induced by the pathway itself, so their appearance is evidence that the pathway ran even after the factor has returned to the cytoplasm. They are a useful late readout when the early window has been missed.

Including one in the panel turns a snapshot into a record of what happened, which is often more robust than trying to catch the peak.

Common questions

Why does the total factor level not change?

Because activation is release and relocalisation, not synthesis. The factor is present in the cytoplasm bound to its inhibitor before stimulation and in the nucleus after it, and a whole cell blot sees the same total either way.

What is the fastest reliable readout?

Disappearance of the inhibitor, which happens within minutes and is easy to see on a blot. It requires a time course fine enough to catch it before resynthesis.

How do I show a fractionation was clean?

Blot a nuclear marker and a cytoplasmic marker on the same membrane and include them in the figure. A translocation claim without those controls is not evidence.

Browse by service class

• Compare Gene synthesis on advertised prices