Classes
There are three classes of SMAD:
- The receptor-regulated Smads (R-SMAD) which include SMAD1, SMAD2, SMAD3, SMAD5 and SMAD8/9
- The common-mediator Smad (co-SMAD) which includes only SMAD4, which interacts with R-SMADs to participate in signaling
- The antagonistic or inhibitory Smads (I-SMAD) which include SMAD6 and SMAD7, which block the activation of R-SMADs and Co-SMADs.
Read more about this topic: SMAD (protein)
Famous quotes containing the word classes:
“When we of the so-called better classes are scared as men were never scared in history at material ugliness and hardship; when we put off marriage until our house can be artistic, and quake at the thought of having a child without a bank-account and doomed to manual labor, it is time for thinking men to protest against so unmanly and irreligious a state of opinion.”
—William James (1842–1910)
“The difference between people isn’t in their class, but in themselves. Only from the middle classes one gets ideas, and from the common people—life itself, warmth. You feel their hates and loves.”
—D.H. (David Herbert)
“There were three classes of inhabitants who either frequent or inhabit the country which we had now entered: first, the loggers, who, for a part of the year, the winter and spring, are far the most numerous, but in the summer, except for a few explorers for timber, completely desert it; second, the few settlers I have named, the only permanent inhabitants, who live on the verge of it, and help raise supplies for the former; third, the hunters, mostly Indians, who range over it in their season.”
—Henry David Thoreau (1817–1862)