BIOL 300 Lecture Notes - Wild Type, Mitosis, Imaginal Disc
Document Summary
We can divide paracrine signaling into two type: binary (e. g. egf signaling), where the pathways is simply on or off, gradient (e. g. dpp, tgf-bet), meaning you can have different responses depending on ligand concentrations. Gradient signaling involves creation of different responses in different cell types, depending on the concentration of ligand they are exposed to: this method of signaling is economical (the same ligand can be used for many different cells) The theory of gradient signaling was proposed in 1952, called the french. Smad, to allow it to work at much lower concentrations of ligand: the white gene would be somewhere between these two extremes. It is believed that all the conditions above hold true for the dpp (tgf-beta) pathway. To establish gradient signaling, we have to find a pathway: This was first solved in 1996 in drosophila in development of adult organs.