Marc Therrien - Academia.edu (original) (raw)

Papers by Marc Therrien

Nature Reviews Molecular Cell Biology

American journal of medical genetics. Part A, Jan 10, 2018

This report summarizes and highlights the fifth International RASopathies Symposium: When Develop... more This report summarizes and highlights the fifth International RASopathies Symposium: When Development and Cancer Intersect, held in Orlando, Florida in July 2017. The RASopathies comprise a recognizable pattern of malformation syndromes that are caused by germ line mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. Because of their common underlying pathogenetic etiology, there is significant overlap in their phenotypic features, which includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, gastrointestinal and ocular abnormalities, neurological and neurocognitive issues, and a predisposition to cancer. The RAS pathway is a well-known oncogenic pathway that is commonly found to be activated in somatic malignancies. As in somatic cancers, the RASopathies can be caused by various pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. As such, the RASopathies re...

Nature communications, Oct 31, 2017

First-generation RAF inhibitors paradoxically induce ERK signaling in normal and tumor cells exhi... more First-generation RAF inhibitors paradoxically induce ERK signaling in normal and tumor cells exhibiting RAS activity. Compound-induced RAF dimerization through stabilization of the RAF ON/active state by inhibitors has emerged as a critical contributing factor. RAF inhibitors also enhance RAS-RAF association. Although this event is thought to play a key role in priming RAF activation, the underlying mechanism is not known. Here we report that RAF inhibitors induce the disruption of intramolecular interactions between the kinase domain and its N-terminal regulatory region independently of RAS activity. This provides a molecular basis to explain the induction of RAS-RAF association by RAF inhibitors, as well as the co-operativity observed between RAS activity and RAF kinase inhibitors in driving RAF activation. Profiling of second-generation RAF inhibitors confirmed their improved mode of action, but also revealed liabilities that allowed us to discern two properties of an ideal RAF i...

Nature Chemical Biology, 2016

RAS GTPases are important mediators of oncogenesis in humans. However, pharmacological inhibition... more RAS GTPases are important mediators of oncogenesis in humans. However, pharmacological inhibition of RAS has proved challenging. Here we describe a functionally critical region, located outside the effector lobe of RAS, that can be targeted for inhibition. We developed NS1, a synthetic binding protein (monobody) that bound with high affinity to both GTP- and GDP-bound states of H-RAS and K-RAS but not N-RAS. NS1 potently inhibited growth factor signaling and oncogenic H-RAS- and K-RAS-mediated signaling and transformation but did not block oncogenic N-RAS, BRAF or MEK1. NS1 bound the α4-β6-α5 region of RAS, which disrupted RAS dimerization and nanoclustering and led to blocking of CRAF-BRAF heterodimerization and activation. These results establish the importance of the α4-β6-α5 interface in RAS-mediated signaling and define a previously unrecognized site in RAS for inhibiting RAS function.

PLoS biology, 2016

RAS-induced MAPK signaling is a central driver of the cell proliferation apparatus. Disruption of... more RAS-induced MAPK signaling is a central driver of the cell proliferation apparatus. Disruption of this pathway is widely observed in cancer and other pathologies. Consequently, considerable effort has been devoted to understanding the mechanistic aspects of RAS-MAPK signal transmission and regulation. While much information has been garnered on the steps leading up to the activation and inactivation of core pathway components, comparatively little is known on the mechanisms controlling their expression and turnover. We recently identified several factors that dictate Drosophila MAPK levels. Here, we describe the function of one of these, the deubiquitinase (DUB) USP47. We found that USP47 acts post-translationally to counteract a proteasome-mediated event that reduces MAPK half-life and thereby dampens signaling output. Using an RNAi-based genetic interaction screening strategy, we identified UBC6, POE/UBR4, and UFD4, respectively, as E2 and E3 enzymes that oppose USP47 activity. Fu...

Nature, Sep 2, 2009

The ERK (extracellular signal-regulated kinase) pathway is an evolutionarily conserved signal tra... more The ERK (extracellular signal-regulated kinase) pathway is an evolutionarily conserved signal transduction module that controls cellular growth, differentiation and survival. Activation of receptor tyrosine kinases (RTKs) by the binding of growth factors initiates GTP loading of RAS, which triggers the initial steps in the activation of the ERK pathway by modulating RAF family kinase function. Once activated, RAF participates in a sequential cascade of phosphorylation events that activate MEK, and in turn ERK. Unbridled signalling through the ERK pathway caused by activating mutations in RTKs, RAS or RAF has been linked to several human cancers. Of note, one member of the RAF family, BRAF, is the most frequently mutated oncogene in the kinase superfamily. Not surprisingly, there has been a colossal effort to understand the underlying regulation of this family of kinases. In particular, the process by which the RAF kinase domain becomes activated towards its substrate MEK remains of topical interest. Here, using Drosophila Schneider S2 cells, we demonstrate that RAF catalytic function is regulated in response to a specific mode of dimerization of its kinase domain, which we term the side-to-side dimer. Moreover, we find that the RAF-related pseudo-kinase KSR (kinase suppressor of Ras) also participates in forming side-to-side heterodimers with RAF and can thereby trigger RAF activation. This mechanism provides an elegant explanation for the longstanding conundrum about RAF catalytic activation, and also provides an explanation for the capacity of KSR, despite lacking catalytic function, to directly mediate RAF activation. We also show that RAF side-to-side dimer formation is essential for aberrant signalling by oncogenic BRAF mutants, and identify an oncogenic mutation that acts specifically by promoting side-to-side dimerization. Together, our data identify the side-to-side dimer interface of RAF as a potential therapeutic target for intervention in BRAF-dependent tumorigenesis.

F1000 - Post-publication peer review of the biomedical literature, 2000

F1000 - Post-publication peer review of the biomedical literature, 2009

F1000 - Post-publication peer review of the biomedical literature, 2010

Protein scaffolds play an important role in signal transduction, regulating the localization of s... more Protein scaffolds play an important role in signal transduction, regulating the localization of signaling components and mediating key protein interactions. Here, we report that the major binding partners of the Connector Enhancer of KSR 1 (CNK1) scaffold are members of the cytohesin family of Arf guanine nucleotide exchange factors, and that the CNK1/cytohesin interaction is critical for activation of the PI3K/AKT cascade downstream from insulin and insulin-like growth factor 1 (IGF-1) receptors. We identified a domain located in the C-terminal region of CNK1 that interacts constitutively with the coiled-coil domain of the cytohesins, and found that CNK1 facilitates the membrane recruitment of cytohesin-2 following insulin stimulation. Moreover, through protein depletion and rescue experiments, we found that the CNK1/cytohesin interaction promotes signaling from plasma membrane-bound Arf GTPases to the phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) to generate a PIP 2-rich microenvironment that is critical for the membrane recruitment of insulin receptor substrate 1 (IRS1) and signal transmission to the PI3K/AKT cascade. These findings identify CNK1 as a new positive regulator of insulin signaling.

F1000 - Post-publication peer review of the biomedical literature, 2010

F1000 - Post-publication peer review of the biomedical literature, 2011

Background: A very early step in splice site recognition is exon definition, a process that is as... more Background: A very early step in splice site recognition is exon definition, a process that is as yet poorly understood. Communication between the two ends of an exon is thought to be required for this step. We report genome-wide evidence for exons being defined through the combinatorial activity of motifs located in flanking intronic regions. Results: Strongly co-occurring motifs were found to specifically reside in four intronic regions surrounding a large number of human exons. These paired motifs occur around constitutive and alternative exons but not pseudo exons. Most co-occurring motifs are limited to intronic regions within 100 nucleotides of the exon. They are preferentially associated with weaker exons. Their pairing is conserved in evolution and they exhibit a lower frequency of single nucleotide polymorphism when paired. Paired motifs display specificity with respect to distance from the exon borders and in constitutive versus alternative splicing. Many resemble binding sites for heterogeneous nuclear ribonucleoproteins. Specific pairs are associated with tissue-specific genes, the higher expression of which coincides with that of the pertinent RNA binding proteins. Tested pairs acted synergistically to enhance exon inclusion, and this enhancement was found to be exon-specific. Conclusions: The exon-flanking sequence pairs identified here by genomic analysis promote exon inclusion and may play a role in the exon definition step in pre-mRNA splicing. We propose a model in which multiple concerted interactions are required between exonic sequences and flanking intronic sequences to effect exon definition.

F1000 - Post-publication peer review of the biomedical literature, 2012

Nature Reviews Molecular Cell Biology

American journal of medical genetics. Part A, Jan 10, 2018

This report summarizes and highlights the fifth International RASopathies Symposium: When Develop... more This report summarizes and highlights the fifth International RASopathies Symposium: When Development and Cancer Intersect, held in Orlando, Florida in July 2017. The RASopathies comprise a recognizable pattern of malformation syndromes that are caused by germ line mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. Because of their common underlying pathogenetic etiology, there is significant overlap in their phenotypic features, which includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, gastrointestinal and ocular abnormalities, neurological and neurocognitive issues, and a predisposition to cancer. The RAS pathway is a well-known oncogenic pathway that is commonly found to be activated in somatic malignancies. As in somatic cancers, the RASopathies can be caused by various pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. As such, the RASopathies re...

Nature communications, Oct 31, 2017

First-generation RAF inhibitors paradoxically induce ERK signaling in normal and tumor cells exhi... more First-generation RAF inhibitors paradoxically induce ERK signaling in normal and tumor cells exhibiting RAS activity. Compound-induced RAF dimerization through stabilization of the RAF ON/active state by inhibitors has emerged as a critical contributing factor. RAF inhibitors also enhance RAS-RAF association. Although this event is thought to play a key role in priming RAF activation, the underlying mechanism is not known. Here we report that RAF inhibitors induce the disruption of intramolecular interactions between the kinase domain and its N-terminal regulatory region independently of RAS activity. This provides a molecular basis to explain the induction of RAS-RAF association by RAF inhibitors, as well as the co-operativity observed between RAS activity and RAF kinase inhibitors in driving RAF activation. Profiling of second-generation RAF inhibitors confirmed their improved mode of action, but also revealed liabilities that allowed us to discern two properties of an ideal RAF i...

Nature Chemical Biology, 2016

RAS GTPases are important mediators of oncogenesis in humans. However, pharmacological inhibition... more RAS GTPases are important mediators of oncogenesis in humans. However, pharmacological inhibition of RAS has proved challenging. Here we describe a functionally critical region, located outside the effector lobe of RAS, that can be targeted for inhibition. We developed NS1, a synthetic binding protein (monobody) that bound with high affinity to both GTP- and GDP-bound states of H-RAS and K-RAS but not N-RAS. NS1 potently inhibited growth factor signaling and oncogenic H-RAS- and K-RAS-mediated signaling and transformation but did not block oncogenic N-RAS, BRAF or MEK1. NS1 bound the α4-β6-α5 region of RAS, which disrupted RAS dimerization and nanoclustering and led to blocking of CRAF-BRAF heterodimerization and activation. These results establish the importance of the α4-β6-α5 interface in RAS-mediated signaling and define a previously unrecognized site in RAS for inhibiting RAS function.

PLoS biology, 2016

RAS-induced MAPK signaling is a central driver of the cell proliferation apparatus. Disruption of... more RAS-induced MAPK signaling is a central driver of the cell proliferation apparatus. Disruption of this pathway is widely observed in cancer and other pathologies. Consequently, considerable effort has been devoted to understanding the mechanistic aspects of RAS-MAPK signal transmission and regulation. While much information has been garnered on the steps leading up to the activation and inactivation of core pathway components, comparatively little is known on the mechanisms controlling their expression and turnover. We recently identified several factors that dictate Drosophila MAPK levels. Here, we describe the function of one of these, the deubiquitinase (DUB) USP47. We found that USP47 acts post-translationally to counteract a proteasome-mediated event that reduces MAPK half-life and thereby dampens signaling output. Using an RNAi-based genetic interaction screening strategy, we identified UBC6, POE/UBR4, and UFD4, respectively, as E2 and E3 enzymes that oppose USP47 activity. Fu...

Nature, Sep 2, 2009

The ERK (extracellular signal-regulated kinase) pathway is an evolutionarily conserved signal tra... more The ERK (extracellular signal-regulated kinase) pathway is an evolutionarily conserved signal transduction module that controls cellular growth, differentiation and survival. Activation of receptor tyrosine kinases (RTKs) by the binding of growth factors initiates GTP loading of RAS, which triggers the initial steps in the activation of the ERK pathway by modulating RAF family kinase function. Once activated, RAF participates in a sequential cascade of phosphorylation events that activate MEK, and in turn ERK. Unbridled signalling through the ERK pathway caused by activating mutations in RTKs, RAS or RAF has been linked to several human cancers. Of note, one member of the RAF family, BRAF, is the most frequently mutated oncogene in the kinase superfamily. Not surprisingly, there has been a colossal effort to understand the underlying regulation of this family of kinases. In particular, the process by which the RAF kinase domain becomes activated towards its substrate MEK remains of topical interest. Here, using Drosophila Schneider S2 cells, we demonstrate that RAF catalytic function is regulated in response to a specific mode of dimerization of its kinase domain, which we term the side-to-side dimer. Moreover, we find that the RAF-related pseudo-kinase KSR (kinase suppressor of Ras) also participates in forming side-to-side heterodimers with RAF and can thereby trigger RAF activation. This mechanism provides an elegant explanation for the longstanding conundrum about RAF catalytic activation, and also provides an explanation for the capacity of KSR, despite lacking catalytic function, to directly mediate RAF activation. We also show that RAF side-to-side dimer formation is essential for aberrant signalling by oncogenic BRAF mutants, and identify an oncogenic mutation that acts specifically by promoting side-to-side dimerization. Together, our data identify the side-to-side dimer interface of RAF as a potential therapeutic target for intervention in BRAF-dependent tumorigenesis.

F1000 - Post-publication peer review of the biomedical literature, 2000

F1000 - Post-publication peer review of the biomedical literature, 2009

F1000 - Post-publication peer review of the biomedical literature, 2010

Protein scaffolds play an important role in signal transduction, regulating the localization of s... more Protein scaffolds play an important role in signal transduction, regulating the localization of signaling components and mediating key protein interactions. Here, we report that the major binding partners of the Connector Enhancer of KSR 1 (CNK1) scaffold are members of the cytohesin family of Arf guanine nucleotide exchange factors, and that the CNK1/cytohesin interaction is critical for activation of the PI3K/AKT cascade downstream from insulin and insulin-like growth factor 1 (IGF-1) receptors. We identified a domain located in the C-terminal region of CNK1 that interacts constitutively with the coiled-coil domain of the cytohesins, and found that CNK1 facilitates the membrane recruitment of cytohesin-2 following insulin stimulation. Moreover, through protein depletion and rescue experiments, we found that the CNK1/cytohesin interaction promotes signaling from plasma membrane-bound Arf GTPases to the phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) to generate a PIP 2-rich microenvironment that is critical for the membrane recruitment of insulin receptor substrate 1 (IRS1) and signal transmission to the PI3K/AKT cascade. These findings identify CNK1 as a new positive regulator of insulin signaling.

F1000 - Post-publication peer review of the biomedical literature, 2010

F1000 - Post-publication peer review of the biomedical literature, 2011

Background: A very early step in splice site recognition is exon definition, a process that is as... more Background: A very early step in splice site recognition is exon definition, a process that is as yet poorly understood. Communication between the two ends of an exon is thought to be required for this step. We report genome-wide evidence for exons being defined through the combinatorial activity of motifs located in flanking intronic regions. Results: Strongly co-occurring motifs were found to specifically reside in four intronic regions surrounding a large number of human exons. These paired motifs occur around constitutive and alternative exons but not pseudo exons. Most co-occurring motifs are limited to intronic regions within 100 nucleotides of the exon. They are preferentially associated with weaker exons. Their pairing is conserved in evolution and they exhibit a lower frequency of single nucleotide polymorphism when paired. Paired motifs display specificity with respect to distance from the exon borders and in constitutive versus alternative splicing. Many resemble binding sites for heterogeneous nuclear ribonucleoproteins. Specific pairs are associated with tissue-specific genes, the higher expression of which coincides with that of the pertinent RNA binding proteins. Tested pairs acted synergistically to enhance exon inclusion, and this enhancement was found to be exon-specific. Conclusions: The exon-flanking sequence pairs identified here by genomic analysis promote exon inclusion and may play a role in the exon definition step in pre-mRNA splicing. We propose a model in which multiple concerted interactions are required between exonic sequences and flanking intronic sequences to effect exon definition.

F1000 - Post-publication peer review of the biomedical literature, 2012