We then asked what we could learn about Torso by comparing Torso activity with downstream ERK activity. Two things surprised us, highlighting that we can’t always accurately infer receptor activity from downstream signaling.

The Toettcher lab recently developed a new class of biosensors for receptor tyrosine kinases (RTKs) called pYtags. They work beautifully in mammalian cell culture. But could pYtags be used to measure endogenous RTK activity in embryos?

elifesciences.org/articles/82863