meningitisThank you for your explanation!
One question: How about the serine phosphorylation? Is it answered by pure memorization that the FOXO TF is serine phosphorylated, or is it a general fact that all TF's are serine-threonine phosphorylated?+2019-06-04T00:20:05Z
tsl19I'm not sure, but it may be as simple as this: ubiquitin-mediated proteolysis is irreversible, but both N/C shuttling and phosphorylation are generally reversible processes. +2019-06-09T18:07:53Z
didelphusI also guessed that FOXO must be a part of the PI3K pathway, since insulin regulates metabolism through PI3K and the question stem specifically mentions that. Phosphorylation is a major part of that pathway, so even indirectly phosphorylation would regulate FOXO. Frustrating question.+42019-06-10T01:44:37Z
alexbAccording to wikipedia (https://en.wikipedia.org/wiki/FOXO1) phosphorylation of FOXO1 is irreversible. This is referring to phosphorylation of serine residues on FOXO by Akt, which occurs in response to insulin. But the NBME answer suggests it's reversible. What's up?+2019-07-01T20:04:18Z
usmle11ai think youre correct cause ubiquitin mediated proteolyis is an irreversible step. +2019-07-05T16:45:50Z