Extracellular inhibitors are commonly used in development to modulate the activities of signalling molecules. Direct visualisation in the Drosophila embryo of Sog, a Dpp/Scw inhibitor, has now revealed a graded distribution established by degradation and endocytosis.
Ashe, H. L. (2002, April 16). BMP signalling: Visualisation of the Sog protein gradient. Current Biology. Cell Press. https://doi.org/10.1016/S0960-9822(02)00798-4