Protein kinase B signaling cascade ; GO:0043491
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PROTEIN KINASE B SIGNALING
PKB = AKT
ACTIVATION OF PKB
PI3K-DEPENDENT PKB/AKT ACTIVATION
- PKB/AKT binds the phosphoinositides PIP2 and PIP3 (generated by PI3K), localizing PKB to the cell membrane.
- Following localization to the membrane, PKB is phosphorylated by its activating kinases (first on Serine by PDK2/mTORC2, and then on Threonine by PDK1)
PI3K-INDEPENDENT PKB/AKT ACTIVATION
- Tyr phosphorylation by ACK1 (rarer form of activation) (see PMID 20333297)
DOWNSTREAM TARGETS OF PKB
- lots and lots and lots
- Bcl-2 family members (e.g. PKB phosphorylates BAD to inhibit its pro-apoptotic function)
- GSK3 (thereby regulate glucose metabolism)
REGULATION OF PKB SIGNALING
- PTEN: PI3K-dep PKB activation is INHIBITED by PTEN, which counteracts the activity of PI3K (dephosphorylates PIP3 to PIP2)
- SHIP Phosphatases: SHIP phosphatases can directly dephosphorylate AKT to inactivate it.
Another intracellular signaling pathway that named after one mediator.
- What is included in PI3K signaling?.... everything ABOVE and BELOW PI3K? Or does PI3K signaling begin WITH the activity of PI3K.