Jo Woodcock - Academia.edu (original) (raw)

Papers by Jo Woodcock

Nature communications, Aug 30, 2017

This corrects the article DOI: 10.1038/ncomms12862.

Nature communications, Jan 27, 2016

The 14-3-3 family of adaptor proteins regulate diverse cellular functions including cell prolifer... more The 14-3-3 family of adaptor proteins regulate diverse cellular functions including cell proliferation, metabolism, adhesion and apoptosis. Platelets express numerous 14-3-3 isoforms, including 14-3-3ζ, which has previously been implicated in regulating GPIbα function. Here we show an important role for 14-3-3ζ in regulating arterial thrombosis. Interestingly, this thrombosis defect is not related to alterations in von Willebrand factor (VWF)-GPIb adhesive function or platelet activation, but instead associated with reduced platelet phosphatidylserine (PS) exposure and procoagulant function. Decreased PS exposure in 14-3-3ζ-deficient platelets is associated with more sustained levels of metabolic ATP and increased mitochondrial respiratory reserve, independent of alterations in cytosolic calcium flux. Reduced platelet PS exposure in 14-3-3ζ-deficient mice does not increase bleeding risk, but results in decreased thrombin generation and protection from pulmonary embolism, leading to ...

Current Molecular Medicine, Jul 23, 2012

FTY720 is a recently approved first line therapy for relapsing forms of multiple sclerosis. In th... more FTY720 is a recently approved first line therapy for relapsing forms of multiple sclerosis. In this context, FTY720 is a pro-drug, with its anti-multiple sclerosis, immunosuppressive effects largely elicited following its phosphorylation by sphingosine kinase 2 and subsequent modulation of G protein-coupled sphingosine 1-phosphate (S1P) receptor 1 that induces lymphopenia by altering lymphocyte trafficking. A number of other biological effects of FTY720 have, however, been described, including considerable evidence that this drug also has anti-cancer properties. These other effects of FTY720 are independent of S1P receptors, and appear facilitated by modulation of a range of other recently described protein targets by nonphosphorylated FTY720. Here, we review the direct targets of FTY720 that contribute to its anti-cancer properties. We also discuss other recently described protein effectors that, in combination with S1P receptors, appear to contribute to its immunosuppressive effects.

The anti-inflammatory effects of IL-4 on activated monocytes differ from those on monocyte-derive... more The anti-inflammatory effects of IL-4 on activated monocytes differ from those on monocyte-derived macrophages (MDMac). While IL-4 suppresses LPS-induced IL-1beta , IL-12, IL-10 and TNFalpha production by monocytes, IL-4 suppresses only IL-1beta and IL-12 production by MDMac. The U937 and Mono Mac 6 cell lines have similar cytokine responses to IL-4 as monocytes and MDMac, respectively. The IL-4Ralpha and IL-2Rgamma (gammac) chains are well-characterized components of the IL-4 receptor. Cross-linking studies with 125I-IL-4 revealed that for monocytes and U937 cells, the binding of IL-4 to the receptor components was approximately 1:1 for IL-4Ralpha:gammac. In contrast, for MDMac and Mono Mac 6 cells that have a relative reduction in gammac surface expression, the binding of IL-4 to IL-4Ralpha:gammac was approximately 3:1. Furthermore, IL-4 induced IL-4Ralpha chain phosphorylation more rapidly in MDMac and Mono Mac 6 cells than in monocytes and U937 cells. This study identifies a correlation between altered 125I-IL-4 cross-linking to IL-4Ralpha:gammac, IL-4-induced signaling and regulation of pro-inflammatory cytokine production by IL-4.

Current Topics in Developmental Biology, 2005

Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. ... more Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. 14-3-3 proteins function as dimeric phosphoserine-binding proteins with documented interactions throughout the eukaryotic proteome and are highly conserved in both the animal and plant kingdoms. Binding of 14-3-3 to a client protein can have a range of context-dependent effects, including conformational change, enzyme inhibition, a shielding effect, re-localization, and bridging between two molecules. Proteome-based strategies utilizing mass spectrometry have revealed an unprecedented central stage for 14-3-3 in signal transduction with interacting partners composing at least 0.6% of the cellular proteome. 14-3-3 has been shown to bind to the human GM-CSF, IL-3, and IL-5 receptors and is required for the transmission of cell survival. 14-3-3 is involved in survival-specific signals, acting not only at the receptor level but also at critical steps downstream of the receptor. This phosphoserine-mediated pathway works independently of tyrosine kinases, highlighting an alternative mechanism of signaling for this receptor family. Other growth factor receptors and their adaptors are also being shown to associate with 14-3-3 and/or have putative 14-3-3 interaction sequences, such as the prolactin receptor, IGF-1 receptor, and some G-protein coupled receptors. 14-3-3 proteins are remarkably conserved through eukaryotic organisms and in Drosophila are required for photoreceptor development, learning, timing of cell cycles, and maintenance of cellular polarity. These findings are elevating our initial description of biochemical interactions to a better understanding of 14-3-3 function at the level of the whole organism. Further study should explore the integration of phosphoserine and phosphotyrosine signaling by 14-3-3 proteins and the role of isoform-specific functions in higher organisms. The prevalence of functional 14-3-3 binding sites throughout the proteome, and especially among growth factor receptors and signaling molecules, reflects a global role for 14-3-3 in multiple cellular decision making.

Proceedings of the National Academy of Sciences of the United States of America, Dec 1, 1993

Interleukin (IL)-3 stimulates hemopoiesis in vitro. However, IL-3 is not normafly found in bone m... more Interleukin (IL)-3 stimulates hemopoiesis in vitro. However, IL-3 is not normafly found in bone marrow, raising doubts as to the in vivo role of IL-3. We have found that human umbilical vein endothelial celis (HUVEC) express functional high-affinity receptors for IL-3 after stimulation with tumor necrosis factor a (TNF-a), IL-1,B, or lipopolysaccharide, and that this receptor is involved in inflammatory phenomena. TNF-a caused time-and dose-dependent upregulation of mRNA for the IL-3 receptor a and ,B chains, with maximal effects occurring 16-36 h after stimulation with TNF-a at 100 units/mi. Induction of mRNA correlated with protein expression on the cell surface as judged by monoclonal antibody staining and by the ability of HUVEC to specifically bind 125I-labeled IL-3. Scatchard analysis under optimal conditions of TNF-a stimulation revealed 41500 IL-3 receptors per cell, which were of a high-affinity class (Kd = 500 pM) only.

Oncotarget, May 5, 2015

14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly ... more 14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly dysregulated hallmarks of cancers. 14-3-3 protein expression is enhanced in many human cancers and correlates with more aggressive tumors and poor prognosis, suggesting a role for 14-3-3 proteins in tumorigenesis and/ or progression. We showed previously that the dimeric state of 14-3-3 proteins is regulated by the lipid sphingosine, a physiological inducer of apoptosis. As the functions of 14-3-3 proteins are dependent on their dimeric state, this sphingosinemediated 14-3-3 regulation provides a possible means to target dimeric 14-3-3 for therapeutic effect. However, sphingosine mimics are needed that are not susceptible to sphingolipid metabolism. We show here the identification and optimization of sphingosine mimetics that render dimeric 14-3-3 susceptible to phosphorylation at a site buried in the dimer interface and induce mitochondrial-mediated apoptosis. Two such compounds, RB-011 and RB-012, disrupt 14-3-3 dimers at low micromolar concentrations and induce rapid down-regulation of Raf-MAPK and PI3K-Akt signaling in Jurkat cells. Importantly, both RB-011 and RB-012 induce apoptosis of human A549 lung cancer cells and RB-012, through disruption of MAPK signaling, reduces xenograft growth in mice. Thus, these compounds provide proof-of-principle for this novel 14-3-3-targeting approach for anti-cancer drug discovery.

Developmental cell, Jan 21, 2015

ROCK signaling causes epidermal hyper-proliferation by increasing ECM production, elevating derma... more ROCK signaling causes epidermal hyper-proliferation by increasing ECM production, elevating dermal stiffness, and enhancing Fak-mediated mechano-transduction signaling. Elevated dermal stiffness in turn causes ROCK activation, establishing mechano-reciprocity, a positive feedback loop that can promote tumors. We have identified a negative feedback mechanism that limits excessive ROCK signaling during wound healing and is lost in squamous cell carcinomas (SCCs). Signal flux through ROCK was selectively tuned down by increased levels of 14-3-3ζ, which interacted with Mypt1, a ROCK signaling antagonist. In 14-3-3ζ(-/-) mice, unrestrained ROCK signaling at wound margins elevated ECM production and reduced ECM remodeling, increasing dermal stiffness and causing rapid wound healing. Conversely, 14-3-3ζ deficiency enhanced cutaneous SCC size. Significantly, inhibiting 14-3-3ζ with a novel pharmacological agent accelerated wound healing 2-fold. Patient samples of chronic non-healing wounds ...

Blood, 2007

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine that controls... more Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine that controls the production and function of blood cells, is deregulated in multiple diseases such as asthma, arthritis and leukaemia yet offers therapeutic value in Crohn’s disease and as an adjuvant in anti-cancer therapy. Its receptors are heterodimers consisting of a ligand-specific alpha subunit and a beta subunit which is critical for signalling and is shared with the interleukin (IL)-3 and IL-5 receptors. The latter have also been implicated in pathologies such as acute myeloid leukaemia and allergic inflammation respectively. Despite the clear involvement of this family of receptors in human diseases their three dimensional structures in complex with the cognate ligand is not known and the mechanism by which they signal has remained an enigma. In particular it has baffled scientists that the membrane proximal domains of the beta subunit are 120A apart, too big a distance to allow transphosphorylation of the receptors by their associated JAK-2 kinases and receptor activation. We report here the structure of the human GM-CSF/GM-CSF receptor ternary complex and its assembly into hexamers (comprising 2 molecules of GM-CSF, alpha subunits and beta subunits each) and into unexpected dodecamers or higher order complexes. The dodecamer arrangement allows the interaction of two hexamers through a distinct site 4 which is composed of both alpha and beta subunits. Importantly, mutagenesis of the GM-CSF receptor at the dodecamer interface revealed that whilst site 4 is not involved in high or low affinity binding of ligand it is critical for receptor activation and signalling. This novel form of receptor assembly likely applies also to the IL-3 and IL-5 receptors, providing a structural basis for understanding cytokine receptor activation and for the development of novel therapeutics.

Acta Crystallographica Section A Foundations and Advances, 2014

14-3-3 proteins are a highly conserved family of dimeric phospho-serine binding proteins that mod... more 14-3-3 proteins are a highly conserved family of dimeric phospho-serine binding proteins that modulate the functions of key cellular proteins involved in signaling. 14-3-3ζ plays a prominent role in signaling pathways leading to inhibition of apoptosis, sequestration of tumor suppressor proteins and activation of signalling pathways that promote growth. 14-3-3ζ expression is up-regulated in many human cancers and associated with enhanced survival of cancer cells. The significant association of 14-3-3ζ over expression with disease recurrence and chemo-resistance makes this protein an attractive candidate for anti-cancer therapy. The anti-apoptotic activity of 14-3-3ζ is entirely dependent on the dimeric state of the protein. Our studies have shown that 14-3-3ζ activity is regulated by sphingosine and other lipid analogs that render 14-3-3 phosphorylatable, disrupting its dimeric state thereby leading to apoptosis [1]. Structural studies and mutagenesis on 14-3-3ζ confirm that the dim...

Human granulocyte-macrophage colony-stimu- lating factor (GM-CSF) and interleukin (IL-3) are cyto... more Human granulocyte-macrophage colony-stimu- lating factor (GM-CSF) and interleukin (IL-3) are cytoki- nes active in both normal and abnormal hemopoiesis, inflammation, and immunity. Their biological activity is �mediated via receptors that comprise a ligand-specific a chain and a �3 chain that is common to the GM-CSF, IL-3, and IL-5 receptors. To understand the mechanism of action of GM-CSF and IL-3 in

Oncotarget, Jan 4, 2015

14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly ... more 14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly dysregulated hallmarks of cancers. 14-3-3 protein expression is enhanced in many human cancers and correlates with more aggressive tumors and poor prognosis, suggesting a role for 14-3-3 proteins in tumorigenesis and/or progression. We showed previously that the dimeric state of 14-3-3 proteins is regulated by the lipid sphingosine, a physiological inducer of apoptosis. As the functions of 14-3-3 proteins are dependent on their dimeric state, this sphingosine-mediated 14-3-3 regulation provides a possible means to target dimeric 14-3-3 for therapeutic effect. However, sphingosine mimics are needed that are not susceptible to sphingolipid metabolism. We show here the identification and optimization of sphingosine mimetics that render dimeric 14-3-3 susceptible to phosphorylation at a site buried in the dimer interface and induce mitochondrial-mediated apoptosis. Two such compounds, RB-011...

Blood, Jan 15, 2000

Heterodimeric cytokine receptors generally consist of a major cytokine-binding subunit and a sign... more Heterodimeric cytokine receptors generally consist of a major cytokine-binding subunit and a signaling subunit. The latter can transduce signals by more than 1 cytokine, as exemplified by the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-2 (IL-2), and IL-6 receptor systems. However, often the signaling subunits in isolation are unable to bind cytokines, a fact that has made it more difficult to obtain structural definition of their ligand-binding sites. This report details the crystal structure of the ligand-binding domain of the GM-CSF/IL-3/IL-5 receptor beta-chain (beta(c)) signaling subunit in complex with the Fab fragment of the antagonistic monoclonal antibody, BION-1. This is the first single antagonist of all 3 known eosinophil-producing cytokines, and it is therefore capable of regulating eosinophil-related diseases such as asthma. The structure reveals a fibronectin type III domain, and the antagonist-binding site involves major contributions from t...

Nature communications, Aug 30, 2017

This corrects the article DOI: 10.1038/ncomms12862.

Nature communications, Jan 27, 2016

The 14-3-3 family of adaptor proteins regulate diverse cellular functions including cell prolifer... more The 14-3-3 family of adaptor proteins regulate diverse cellular functions including cell proliferation, metabolism, adhesion and apoptosis. Platelets express numerous 14-3-3 isoforms, including 14-3-3ζ, which has previously been implicated in regulating GPIbα function. Here we show an important role for 14-3-3ζ in regulating arterial thrombosis. Interestingly, this thrombosis defect is not related to alterations in von Willebrand factor (VWF)-GPIb adhesive function or platelet activation, but instead associated with reduced platelet phosphatidylserine (PS) exposure and procoagulant function. Decreased PS exposure in 14-3-3ζ-deficient platelets is associated with more sustained levels of metabolic ATP and increased mitochondrial respiratory reserve, independent of alterations in cytosolic calcium flux. Reduced platelet PS exposure in 14-3-3ζ-deficient mice does not increase bleeding risk, but results in decreased thrombin generation and protection from pulmonary embolism, leading to ...

Current Molecular Medicine, Jul 23, 2012

FTY720 is a recently approved first line therapy for relapsing forms of multiple sclerosis. In th... more FTY720 is a recently approved first line therapy for relapsing forms of multiple sclerosis. In this context, FTY720 is a pro-drug, with its anti-multiple sclerosis, immunosuppressive effects largely elicited following its phosphorylation by sphingosine kinase 2 and subsequent modulation of G protein-coupled sphingosine 1-phosphate (S1P) receptor 1 that induces lymphopenia by altering lymphocyte trafficking. A number of other biological effects of FTY720 have, however, been described, including considerable evidence that this drug also has anti-cancer properties. These other effects of FTY720 are independent of S1P receptors, and appear facilitated by modulation of a range of other recently described protein targets by nonphosphorylated FTY720. Here, we review the direct targets of FTY720 that contribute to its anti-cancer properties. We also discuss other recently described protein effectors that, in combination with S1P receptors, appear to contribute to its immunosuppressive effects.

The anti-inflammatory effects of IL-4 on activated monocytes differ from those on monocyte-derive... more The anti-inflammatory effects of IL-4 on activated monocytes differ from those on monocyte-derived macrophages (MDMac). While IL-4 suppresses LPS-induced IL-1beta , IL-12, IL-10 and TNFalpha production by monocytes, IL-4 suppresses only IL-1beta and IL-12 production by MDMac. The U937 and Mono Mac 6 cell lines have similar cytokine responses to IL-4 as monocytes and MDMac, respectively. The IL-4Ralpha and IL-2Rgamma (gammac) chains are well-characterized components of the IL-4 receptor. Cross-linking studies with 125I-IL-4 revealed that for monocytes and U937 cells, the binding of IL-4 to the receptor components was approximately 1:1 for IL-4Ralpha:gammac. In contrast, for MDMac and Mono Mac 6 cells that have a relative reduction in gammac surface expression, the binding of IL-4 to IL-4Ralpha:gammac was approximately 3:1. Furthermore, IL-4 induced IL-4Ralpha chain phosphorylation more rapidly in MDMac and Mono Mac 6 cells than in monocytes and U937 cells. This study identifies a correlation between altered 125I-IL-4 cross-linking to IL-4Ralpha:gammac, IL-4-induced signaling and regulation of pro-inflammatory cytokine production by IL-4.

Current Topics in Developmental Biology, 2005

Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. ... more Tyrosine and serine phosphorylation are central to cellular signaling in growth and development. 14-3-3 proteins function as dimeric phosphoserine-binding proteins with documented interactions throughout the eukaryotic proteome and are highly conserved in both the animal and plant kingdoms. Binding of 14-3-3 to a client protein can have a range of context-dependent effects, including conformational change, enzyme inhibition, a shielding effect, re-localization, and bridging between two molecules. Proteome-based strategies utilizing mass spectrometry have revealed an unprecedented central stage for 14-3-3 in signal transduction with interacting partners composing at least 0.6% of the cellular proteome. 14-3-3 has been shown to bind to the human GM-CSF, IL-3, and IL-5 receptors and is required for the transmission of cell survival. 14-3-3 is involved in survival-specific signals, acting not only at the receptor level but also at critical steps downstream of the receptor. This phosphoserine-mediated pathway works independently of tyrosine kinases, highlighting an alternative mechanism of signaling for this receptor family. Other growth factor receptors and their adaptors are also being shown to associate with 14-3-3 and/or have putative 14-3-3 interaction sequences, such as the prolactin receptor, IGF-1 receptor, and some G-protein coupled receptors. 14-3-3 proteins are remarkably conserved through eukaryotic organisms and in Drosophila are required for photoreceptor development, learning, timing of cell cycles, and maintenance of cellular polarity. These findings are elevating our initial description of biochemical interactions to a better understanding of 14-3-3 function at the level of the whole organism. Further study should explore the integration of phosphoserine and phosphotyrosine signaling by 14-3-3 proteins and the role of isoform-specific functions in higher organisms. The prevalence of functional 14-3-3 binding sites throughout the proteome, and especially among growth factor receptors and signaling molecules, reflects a global role for 14-3-3 in multiple cellular decision making.

Proceedings of the National Academy of Sciences of the United States of America, Dec 1, 1993

Interleukin (IL)-3 stimulates hemopoiesis in vitro. However, IL-3 is not normafly found in bone m... more Interleukin (IL)-3 stimulates hemopoiesis in vitro. However, IL-3 is not normafly found in bone marrow, raising doubts as to the in vivo role of IL-3. We have found that human umbilical vein endothelial celis (HUVEC) express functional high-affinity receptors for IL-3 after stimulation with tumor necrosis factor a (TNF-a), IL-1,B, or lipopolysaccharide, and that this receptor is involved in inflammatory phenomena. TNF-a caused time-and dose-dependent upregulation of mRNA for the IL-3 receptor a and ,B chains, with maximal effects occurring 16-36 h after stimulation with TNF-a at 100 units/mi. Induction of mRNA correlated with protein expression on the cell surface as judged by monoclonal antibody staining and by the ability of HUVEC to specifically bind 125I-labeled IL-3. Scatchard analysis under optimal conditions of TNF-a stimulation revealed 41500 IL-3 receptors per cell, which were of a high-affinity class (Kd = 500 pM) only.

Oncotarget, May 5, 2015

14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly ... more 14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly dysregulated hallmarks of cancers. 14-3-3 protein expression is enhanced in many human cancers and correlates with more aggressive tumors and poor prognosis, suggesting a role for 14-3-3 proteins in tumorigenesis and/ or progression. We showed previously that the dimeric state of 14-3-3 proteins is regulated by the lipid sphingosine, a physiological inducer of apoptosis. As the functions of 14-3-3 proteins are dependent on their dimeric state, this sphingosinemediated 14-3-3 regulation provides a possible means to target dimeric 14-3-3 for therapeutic effect. However, sphingosine mimics are needed that are not susceptible to sphingolipid metabolism. We show here the identification and optimization of sphingosine mimetics that render dimeric 14-3-3 susceptible to phosphorylation at a site buried in the dimer interface and induce mitochondrial-mediated apoptosis. Two such compounds, RB-011 and RB-012, disrupt 14-3-3 dimers at low micromolar concentrations and induce rapid down-regulation of Raf-MAPK and PI3K-Akt signaling in Jurkat cells. Importantly, both RB-011 and RB-012 induce apoptosis of human A549 lung cancer cells and RB-012, through disruption of MAPK signaling, reduces xenograft growth in mice. Thus, these compounds provide proof-of-principle for this novel 14-3-3-targeting approach for anti-cancer drug discovery.

Developmental cell, Jan 21, 2015

ROCK signaling causes epidermal hyper-proliferation by increasing ECM production, elevating derma... more ROCK signaling causes epidermal hyper-proliferation by increasing ECM production, elevating dermal stiffness, and enhancing Fak-mediated mechano-transduction signaling. Elevated dermal stiffness in turn causes ROCK activation, establishing mechano-reciprocity, a positive feedback loop that can promote tumors. We have identified a negative feedback mechanism that limits excessive ROCK signaling during wound healing and is lost in squamous cell carcinomas (SCCs). Signal flux through ROCK was selectively tuned down by increased levels of 14-3-3ζ, which interacted with Mypt1, a ROCK signaling antagonist. In 14-3-3ζ(-/-) mice, unrestrained ROCK signaling at wound margins elevated ECM production and reduced ECM remodeling, increasing dermal stiffness and causing rapid wound healing. Conversely, 14-3-3ζ deficiency enhanced cutaneous SCC size. Significantly, inhibiting 14-3-3ζ with a novel pharmacological agent accelerated wound healing 2-fold. Patient samples of chronic non-healing wounds ...

Blood, 2007

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine that controls... more Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine that controls the production and function of blood cells, is deregulated in multiple diseases such as asthma, arthritis and leukaemia yet offers therapeutic value in Crohn’s disease and as an adjuvant in anti-cancer therapy. Its receptors are heterodimers consisting of a ligand-specific alpha subunit and a beta subunit which is critical for signalling and is shared with the interleukin (IL)-3 and IL-5 receptors. The latter have also been implicated in pathologies such as acute myeloid leukaemia and allergic inflammation respectively. Despite the clear involvement of this family of receptors in human diseases their three dimensional structures in complex with the cognate ligand is not known and the mechanism by which they signal has remained an enigma. In particular it has baffled scientists that the membrane proximal domains of the beta subunit are 120A apart, too big a distance to allow transphosphorylation of the receptors by their associated JAK-2 kinases and receptor activation. We report here the structure of the human GM-CSF/GM-CSF receptor ternary complex and its assembly into hexamers (comprising 2 molecules of GM-CSF, alpha subunits and beta subunits each) and into unexpected dodecamers or higher order complexes. The dodecamer arrangement allows the interaction of two hexamers through a distinct site 4 which is composed of both alpha and beta subunits. Importantly, mutagenesis of the GM-CSF receptor at the dodecamer interface revealed that whilst site 4 is not involved in high or low affinity binding of ligand it is critical for receptor activation and signalling. This novel form of receptor assembly likely applies also to the IL-3 and IL-5 receptors, providing a structural basis for understanding cytokine receptor activation and for the development of novel therapeutics.

Acta Crystallographica Section A Foundations and Advances, 2014

14-3-3 proteins are a highly conserved family of dimeric phospho-serine binding proteins that mod... more 14-3-3 proteins are a highly conserved family of dimeric phospho-serine binding proteins that modulate the functions of key cellular proteins involved in signaling. 14-3-3ζ plays a prominent role in signaling pathways leading to inhibition of apoptosis, sequestration of tumor suppressor proteins and activation of signalling pathways that promote growth. 14-3-3ζ expression is up-regulated in many human cancers and associated with enhanced survival of cancer cells. The significant association of 14-3-3ζ over expression with disease recurrence and chemo-resistance makes this protein an attractive candidate for anti-cancer therapy. The anti-apoptotic activity of 14-3-3ζ is entirely dependent on the dimeric state of the protein. Our studies have shown that 14-3-3ζ activity is regulated by sphingosine and other lipid analogs that render 14-3-3 phosphorylatable, disrupting its dimeric state thereby leading to apoptosis [1]. Structural studies and mutagenesis on 14-3-3ζ confirm that the dim...

Human granulocyte-macrophage colony-stimu- lating factor (GM-CSF) and interleukin (IL-3) are cyto... more Human granulocyte-macrophage colony-stimu- lating factor (GM-CSF) and interleukin (IL-3) are cytoki- nes active in both normal and abnormal hemopoiesis, inflammation, and immunity. Their biological activity is �mediated via receptors that comprise a ligand-specific a chain and a �3 chain that is common to the GM-CSF, IL-3, and IL-5 receptors. To understand the mechanism of action of GM-CSF and IL-3 in

Oncotarget, Jan 4, 2015

14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly ... more 14-3-3 proteins play a pivotal role in controlling cell proliferation and survival, two commonly dysregulated hallmarks of cancers. 14-3-3 protein expression is enhanced in many human cancers and correlates with more aggressive tumors and poor prognosis, suggesting a role for 14-3-3 proteins in tumorigenesis and/or progression. We showed previously that the dimeric state of 14-3-3 proteins is regulated by the lipid sphingosine, a physiological inducer of apoptosis. As the functions of 14-3-3 proteins are dependent on their dimeric state, this sphingosine-mediated 14-3-3 regulation provides a possible means to target dimeric 14-3-3 for therapeutic effect. However, sphingosine mimics are needed that are not susceptible to sphingolipid metabolism. We show here the identification and optimization of sphingosine mimetics that render dimeric 14-3-3 susceptible to phosphorylation at a site buried in the dimer interface and induce mitochondrial-mediated apoptosis. Two such compounds, RB-011...

Blood, Jan 15, 2000

Heterodimeric cytokine receptors generally consist of a major cytokine-binding subunit and a sign... more Heterodimeric cytokine receptors generally consist of a major cytokine-binding subunit and a signaling subunit. The latter can transduce signals by more than 1 cytokine, as exemplified by the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-2 (IL-2), and IL-6 receptor systems. However, often the signaling subunits in isolation are unable to bind cytokines, a fact that has made it more difficult to obtain structural definition of their ligand-binding sites. This report details the crystal structure of the ligand-binding domain of the GM-CSF/IL-3/IL-5 receptor beta-chain (beta(c)) signaling subunit in complex with the Fab fragment of the antagonistic monoclonal antibody, BION-1. This is the first single antagonist of all 3 known eosinophil-producing cytokines, and it is therefore capable of regulating eosinophil-related diseases such as asthma. The structure reveals a fibronectin type III domain, and the antagonist-binding site involves major contributions from t...