Protein interaction switches coordinate Raf-1 and MST2/Hippo signalling
David Romano1, Lan K Nguyen1, David Matallanas1
1Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.
Nature Cell Biology
|June 16, 2014
Summary
Competing protein interactions regulate cellular signaling pathways, acting as switches. This mechanism integrates signals, controlling cell fate decisions like apoptosis and proliferation.
Area of Science:
- Cellular signaling
- Molecular biology
- Systems biology
Background:
- Signal transduction pathways must be coordinated for proper cellular function.
- Raf-1 is a key regulator linking the MST-LATS and MEK-ERK pathways in mammalian cells.
Purpose of the Study:
- To elucidate the regulatory mechanisms coordinating crosstalk between ERK and MST pathways.
- To investigate how competing protein interactions drive signal transduction switches.
Main Methods:
- Mathematical modeling of signaling pathways.
- Experimental validation of predicted interactions.
- Analysis of protein phosphorylation and binding affinities.
Main Results:
- A complex network of competing protein interactions coordinates ERK and MST pathway crosstalk.
- Phosphorylation-dependent binding affinity changes mediate steep signaling switches.
- Akt phosphorylation of MST2 and LATS1 feedback phosphorylation of Raf-1 Ser259 were identified as key regulatory events.
- Raf-1 Ser259 phosphorylation suppresses both MST2 and MEK signaling.
Conclusions:
- Competing protein interactions provide a versatile mechanism for signal distribution.
- This circuitry allows dynamic integration of graded signals into switch-like cellular responses.
- Dysregulation of these interactions, as seen in Raf-1 Ser259 mutants or MST2 downregulation, can lead to aberrant cell proliferation, transformation, and survival.
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