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Citation
Douziech, M., Sahmi, M., Laberge, G., Therrien, M. (2006). A KSR/CNK complex mediated by HYP, a novel SAM domain-containing protein, regulates RAS-dependent RAF activation in Drosophila.  Genes Dev. 20(7): 807--819.
FlyBase ID
FBrf0190541
Publication Type
Research paper
Abstract

RAF is a critical effector of the small GTPase RAS in normal and malignant cells. Despite intense scrutiny, the mechanism regulating RAF activation remains partially understood. Here, we show that the scaffold KSR (kinase suppressor of RAS), a RAF homolog known to assemble RAF/MEK/ERK complexes, induces RAF activation in Drosophila by a mechanism mediated by its kinase-like domain, but which is independent of its scaffolding property or putative kinase activity. Interestingly, we found that KSR is recruited to RAF prior to signal activation by the RAF-binding protein CNK (connector enhancer of KSR) in association with a novel SAM (sterile alpha motif) domain-containing protein, named Hyphen (HYP). Moreover, our data suggest that the interaction of KSR to CNK/HYP stimulates the RAS-dependent RAF-activating property of KSR. Together, these findings identify a novel protein complex that controls RAF activation and suggest that KSR does not only act as a scaffold for the MAPK (mitogen-activated protein kinase) module, but may also function as a RAF activator. By analogy to catalytically impaired, but conformationally active B-RAF oncogenic mutants, we discuss the possibility that KSR represents a natural allosteric inducer of RAF catalytic function.

PubMed ID
PubMed Central ID
PMC1472284 (PMC) (EuropePMC)
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    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    Genes Dev.
    Title
    Genes & Development
    Publication Year
    1987-
    ISBN/ISSN
    0890-9369
    Data From Reference
    Alleles (9)
    Genes (9)
    Natural transposons (1)
    Experimental Tools (1)
    Transgenic Constructs (6)