How Protein Kinase B is Activated in Cells
Author Information
Author(s): Calleja Véronique, Alcor Damien, Laguerre Michel, Park Jongsun, Vojnovic Borivoj, Hemmings Brian A, Downward Julian, Parker Peter J, Larijani Banafshé
Primary Institution: Cancer Research UK, London Research Institute
Hypothesis
The study investigates the molecular mechanisms of Protein Kinase B (PKB) activation by its regulator, PDK1, in vivo.
Conclusion
The study reveals that PKB remains inactive in a 'PH-in' conformation until it is recruited to the plasma membrane, where it changes to an active 'PH-out' conformation.
Supporting Evidence
- PKB and PDK1 interact in the cytoplasm and translocate to the plasma membrane upon stimulation.
- The 'PH-in' conformation of PKB prevents its activation until it is recruited to the membrane.
- Fluorescence lifetime imaging microscopy was used to monitor PKB conformational changes in live cells.
- Blocking the PH domain interaction alters PKB activation dynamics.
- PDK1 phosphorylation of PKB occurs only when PKB adopts the 'PH-out' conformation.
Takeaway
This study shows that a protein called PKB can switch from being inactive to active when it moves to a specific part of the cell, which is important for understanding how cells grow and survive.
Methodology
The study used Förster resonance energy transfer (FRET) and fluorescence lifetime imaging microscopy to observe PKB and PDK1 interactions in live cells.
Limitations
The study primarily focuses on a specific cell line (NIH3T3) and may not fully represent PKB behavior in other cell types.
Statistical Information
P-Value
0.002
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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