Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Biotech / Medical : Ligand (LGND) Breakout! -- Ignore unavailable to you. Want to Upgrade?

To: Peter Singleton who wrote (16321)	3/3/1998 1:32:00 PM
From: squetch	Respond to of 32384

Here is one I just happened to see. Humna Malignant Mesothelioma Cell Growth: Activation of JAK/STAT1 for Inhibition by IFN-gamma. >>In cells that were responding poorly to growth inhibition, we observed impaired activation of key components of the cellular signaling pathway, such as JAK2 and STAT1, or of other downstream transcription factors.<<

To: Peter Singleton who wrote (16321)	3/3/1998 2:04:00 PM
From: Henry Niman	Read Replies (1) \| Respond to of 32384

Peter, You can think of phosphorylation as a toggle switch. The enzyme is actived when a kinase puts a phosphate on and its deactivated when a phosphorylase takes the phosphate off. Three of the 20 amino acids in a protein can be phosphorylated (serine, threonine, and tyrosine), but for the JAKs Kinases, its a tyrosine that is phosphorylated. Most of the poplypeptide hormone receptors bind a growth factor or interleukin outside the cell which causes a shape change which then activates the kinase. This kinase can the phosporylate a transcription factor, thereby activating it. For the IRs, the hormone is small, so it goes through the cell membrane and then activates the transcription factor by binding to it. The target of the HER2/neu antibody is a kinase related to EGF, so I assume that it also goes through the JAKs/STAT pathway. There are many tyrosine kinases, which is why the JAKs class was initially called Just Another Kinase.