In 1954 Edwin Krebs and Edmond Fischer show that glycogen phosphorylase is switched by a phosphate group.
The Visitor presses a hormone molecule against a receptor and watches the message travel inward.
The Layer That Ties It Together
- A hormone, growth factor, or neurotransmitter binds a receptor and starts a cascade that turns an outside message into an inside response. A single receptor activation can yield thousands of second messengers within milliseconds.
- The MAP kinase module runs Raf, then MEK, then ERK, with each step amplifying about 10-fold for a cascade total near 106. Receptors number about 2,000 GPCRs plus about 58 receptor tyrosine kinases.
- A human cell holds 518 kinases and 147 phosphatases in one shared space. Scaffold proteins such as KSR hold kinases and their substrates together so that each growth factor reaches its own pathway. Phosphatases end signals and reset the pathway.
- The page names signaling as the layer that ties the other eleven systems together. It tells the cell when to replicate DNA (System 01), modify histones (System 03), and fold stress proteins (System 11).
One binding event at the membrane becomes a cascade, each tier about 10 times wider. The site page carries the kinase counts and the scaffolds.
What job do scaffold proteins do?
They hold kinases and their substrates in proximity so each pathway reaches the right targets.
Signaling connects all twelve systems and tells each one when to act.
The Visitor lights node 12. All twelve nodes glow on the coherence map.
See the map