Disease-causing RRAS mutations are activating and act by maintaining the GTPase in its GTP-bound active state.
We also demonstrate that RASopathy-causing RRAS mutations are activating and promote signalling perturbation by enhancing stimulus-dependent MEK, ERK and, at a lower extent, AKT phosphorylation.
This contrasts with what has been observed for mutations in the ATP-binding site that completely abolished ATP inhibition in the absence of Mg2+, such as R50P and G334D: channels containing these mutations were activated by MgATP [ 33, 34].
All MAP2K1 mutations were activating missense mutations localized to exons 2 and 3, which encode negative regulatory and catalytic domains, respectively.
The remarkable absence of any frameshift or nonsense mutations, deletions, or epigenetic silencing provided early evidence that IDH mutations were activating (Flanagan et al., 2012; Zhao et al., 2009).
Three PIK3CA mutations were "activating" (one with E542K and two with H1047N mutations).
Other somatic mutations that appear linked to H3K27M mutation are activating mutations in ACVR1 (activin receptor type 1) that enhance BMP (bone morphogenetic protein) signaling (Fontebasso et al. 2014; Wu et al. 2014; Buczkowicz et al. 2014; Taylor et al. 2014a).
Additionally, when an oncogene mutation was activated at the same time as the gene for PTF1A was deleted, Krah et al. observed the rapid formation of large numbers of malignant pancreatic tumors in the mice.
Even newer genetic-engineering technologies have given researchers the ability to control when and where a specific gene or mutation is activated or deleted, allowing investigators to narrow the role of the gene's function to circumscribed neural pathways and across development.
Resistance occurs secondary to emergence of AR somatic point mutations that are activated by prednisolone but not by dexamethasone.
