fuel sensor of the cell
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For more information see
Biochemistry Online: Chapter 9C - Signal Transduction - Kinases and Phosphatases
II. General Structure
- missing C terminal flexible loop (471-523)
The alpha subunit is the catalytic subunit. When phosphorylated
on Thr 172, its activity increases 100X.
Add Beta Subunit
The carboxy-terminal domain is shown
Add Gamma Subunit
The gamma subunit binds AXP (AMP, ADP, ATP) at 4 possible binding
sites. Site 2 is unoccupied, site 4 has an AMP seemingly always
bound. Sites 1 binds all AXP with similarly high affinity (50x
greater than site 3) and allosterically increases the activity of
the phosphorylated from 2-5X. Occupancy of site 3 affects
dephosphorylation of T172.
Add AMP (spacefill)
AMP is shown bound to site 3 and 4.
Staurosporine is a high affinity competitive inhibitor of ATP
binding to the catalytic site of many protein kinases
Add pThr (A172
When AMP is bound to site 3, pThr 172 can't be dephosphorylated.
If ADP rises in the cell, it displaces ATP at site 3 and also
prevents dephosphorylation of pT172.