General Functions of The JAK Family
Since members of the type I and type II cytokine receptor families possess no catalytic kinase activity, they rely on the JAK family of tyrosine kinases to phosphorylate and activate downstream proteins involved in their signal transduction pathways. The receptors exist as paired polypeptides, thus exhibiting two intracellular signal-transducing domains. JAKs associate with a proline-rich region in each intracellular domain, which is adjacent to the cell membrane and called a box1/box2 region. After the receptor associates with its respective cytokine/ligand, it goes through a conformational change, bringing the two JAKs close enough to phosphorylate each other. The JAK autophosphorylation induces a conformational change within itself, enabling it to transduce the intracellular signal by further phosphorylating and activating transcription factors called STATs (Signal Transducer and Activator of Transcription, or Signal Transduction And Transcription). The activated STATs dissociate from the receptor and form dimers before translocating to the cell nucleus, where they regulate transcription of selected genes.
Some examples of the molecules that use the JAK/STAT signaling pathway are colony-stimulating factor, prolactin, growth hormone, and many cytokines.
Read more about this topic: Janus Kinase
Famous quotes containing the words general, functions and/or family:
“It has been an unchallengeable American doctrine that cranberry sauce, a pink goo with overtones of sugared tomatoes, is a delectable necessity of the Thanksgiving board and that turkey is uneatable without it.... There are some things in every country that you must be born to endure; and another hundred years of general satisfaction with Americans and America could not reconcile this expatriate to cranberry sauce, peanut butter, and drum majorettes.”
—Alistair Cooke (b. 1908)
“One of the most highly valued functions of used parents these days is to be the villains of their children’s lives, the people the child blames for any shortcomings or disappointments. But if your identity comes from your parents’ failings, then you remain forever a member of the child generation, stuck and unable to move on to an adulthood in which you identify yourself in terms of what you do, not what has been done to you.”
—Frank Pittman (20th century)
“The touchstone for family life is still the legendary “and so they were married and lived happily ever after.” It is no wonder that any family falls short of this ideal.”
—Salvador Minuchin (20th century)