The phrase "activation is defective" is correct and usable in written English.
It can be used in contexts where you are describing a malfunction or issue related to an activation process, such as in technology or product functionality.
Example: "After several attempts to start the device, we concluded that the activation is defective and needs to be repaired."
Alternatives: "activation is faulty" or "activation is malfunctioning".
Importantly, even in response to the very high insulin levels utilized in this differentiation protocol (830 nM), Akt activation is defective in both Tsc1−/− and Tsc2−/− MEFs (Figure S1, panels A and B).
Using two independent methods, we found that AMPA receptor internalization following NMDA receptor activation is defective in Vac14 −/− neurons.
A splice variant of MyD88, termed MyD88 short (MyD88s), induced upon LPS activation, is defective in its ability to induce IRAK phosphorylation and behaves as dominant-negative inhibitor [ 79].
We show that mouse aorta endothelial cells express functional CFTR channels, and that their activation is defective in mouse aorta endothelium of trp4-deficient mice, although these cells still expressed the CFTR transcripts.
In cystic fibrosis cells, PKC-dependent channel inactivation was normal, but activation was defective.
Consistently, we found that VP16- and CPT-induced NF-κB activation were defective in MALT1-deficient cells compared with controls (Fig. 1B), indicating that MALT1 is required for DNA damage-induced NF-κB activation.
Unlike MEKK1, MEKK3 knockout is embryonic lethal [ 32] and JNK and p38 activation are defective in MEKK3-/ MEFs stimulated with IL-1β [ 21].
Furthermore, we found that the GEF Dock7 reconstitutes this oscillatory Ca2+ behavior in B6A4C1 cells (Fig. 4F,I), strengthening the conclusion that the activation of Cdc42 is defective in the mutant RBL cells.
Additionally, IL1-induced JNK and p38 activation is completely defective in cells lacking IRAK4.
TorsinA displays LAP1 and LULL1-dependent ATPase activity, while the torsinAΔE protein is defective in this activation (Zhao et al., 2013).
As a consequence, the ∆tdh1 mutant is defective in activation of the Spc1 MAPK by peroxide stress but not other forms of stress.
