Welcome to the Boivin Laboratory! The projects in my laboratory aim to elucidate the function of protein tyrosine phosphatases, which are key regulators in the signalling of reactive oxygen species, so that we can clarify the essential role of the members of this enzyme family in cardiovascular physiology and pathophysiology.
Dr. Benoit Boivin, Ph.D. Researcher
Dr. Benoit Boivin is a researcher and an assistant professor in the Department of Medicine at the Faculty of Medicine of Université de Montréal. His research at the Montreal Heart Institute Research Centre aims to unravel the molecular mechanisms associated with cardiac hypertrophy. He uses diverse biochemical approaches to specifically study how protein tyrosine phosphatases control the signalling pathways that cause cardiac hypertrophy and heart failure. After receiving his specialized doctorate in Biochemistry from Université de Montréal in 2006 on the organization of the endothelin signal transduction system in ventricular cardiomyocytes, Dr. Boivin continued his training as a postdoctoral fellow at the Cold Spring Harbor Laboratory (CHSL) Cancer Center in suburban New York and worked on the redox regulation of protein tyrosine phosphatases in cancer. His work has been rewarded with many research and equipment grants (Fonds de la recherche du Québec – Santé, Heart and Stroke Foundation of Canada, CHSL Association, Canada Foundation for Innovation). He has also received awards of merit, such as the Jean-Louis Lévesque Award from the Montreal Heart Institute Foundation.
Dominic Melançon, MSc. Research Assistant
Dominic joined the laboratory as a research assistant in July 2012. He is involved in developing molecular, cellular and biochemical tools to characterize protein tyrosine phosphatases and redox signalling in cardiac hypertrophy. He was formerly a research associate in R&D. Through his expertise, he is involved in discovery and development for a therapeutic and diagnostic program for prostate cancer. He was also a research associate in the field of protein chemistry for the vaccinology research unit at the CHUL. He was responsible for developing protein purification methods. Dominic received his bachelor's in Microbiology from Université Laval in 2002 and his master's in Microbiology again from Université Laval in 2003. In his free time, Dominic is an avid runner, and he has run a number of marathons and ultramarathons.
Historically, the main function of reactive oxygen species (ROS) has been as an oxidant; ROS therefore cause cellular damage through a process generally called “oxidative stress.” However, we and other research groups have shown that ROS can be involved in physiological and pathophysiological cell signalling by causing the inactivation of protein tyrosine phosphatases (PTPs) in a specific way. The projects in my laboratory aim to elucidate the role of PTPs, which are key regulators in ROS signalling. The members of the PTP family also control many signalling pathways, some of which can lead to cell growth, proliferation, senescence and death. Our work mainly focuses on their role in cardiac pathophysiology.
To date, research on ROS has clarified the role of some signalling networks that control cellular homeostasis in physiological and pathophysiological conditions. ROS are now considered as regulators of many cellular functions (such as migration, autophagy and senescence) and physiological mechanisms (such as vascular tone, glycemia and cardiac hypertrophy).
Phosphorylation is a dynamic and reversible process in which the net phosphorylation of a substrate reflects the coordinated activity of protein kinases that phosphorylize the substrate and protein phosphatases that catalyze the substrate's dephosphorylation. However, in response to extracellular signals, the controlled and localized production of ROS acts as an additional level of control on the signalling of phosphoproteins by regulating the phosphohydrolytic activity of the members of the PTP family.
This regulation of the catalytic activity of PTPs is determined by the architecture of the active site of this family of enzymes, characterized by the signature motif His-Cys-(X)5-Arg-(Ser/Thr) located at the base of the active site cavity, which creates an acidifying environment as it lowers the pKa of catalytic cysteine. This acidifying environment leads to the deprotonation of the side chain of catalytic cysteine into thiolate anions, which makes cysteine an excellent nucleophile for the phosphates of its substrates while making it particularly vulnerable to cellular oxidants (ROS). In other words, the oxidation of catalytic cysteine of specific PTPs neutralizes their catalytic activity and facilitates phosphorylation-dependent signalling.
The nearly one hundred members of the PTP family encoded in the human genome are potentially regulated by the oxidation of their catalytic cysteine to a sulphenic acid. This modification is reversible, and the reduction of inactivated PTPs stops the signal triggered by protein kinases. We have developed a new methodological approach (cysteinyl-labeling assay) that can capture, purify and identify PTPs that have been reversibly oxidized in vivo.
For part of the research in my laboratory, we use this methodological approach to identify the PTPs that are specifically inactivated in a given signalling pathway and that represent a critical control point in the development of cardiac pathologies.
Another more technical focus in my laboratory is to develop new complementary approaches, in collaboration with other laboratories, based on the cysteinyl-labeling assay. The goal of these approaches is to develop specific PTP probes that can be used to: 1) identify oxidized PTPs using mass spectrometry; 2) locate PTP inactivation in the cell through in situ immunofluorescence; and 3) determine the post-translational modifications that reduce PTPs, depending on the cell model and the activated signalling pathway.
Other projects on the role of PTP1B and PTPalpha in the hypertrophic heart are also being developed.
- Boivin, B., Khairallah, M., Cartier, R. and Allen, B.G. (2012) Characterization of hsp27 kinases activited by elevated aortic pressure in heart. Mol Cell Biochem. 371(1-2):31-42 [Pubmed]
- Boivin, B., Yang, M., Tonks, N.K. (2010) Targeting the reversibly oxidized protein tyrosine phosphatase superfamily. Sci. Signal. 3 (137):pl2 [Pubmed]
- Boivin, B., Tonks, N.K. (2010) Analysis of the redox regulation of protein tyrosine phosphatase superfamily members utilizing a cysteinyl-labeling assay. Methods in Enzymol. 474, 35-50. [Pubmed]
- Loh, K., Deng, H., Fukushima, A., Cai, X., Boivin, B., Galic, S., Bruce, C., Shields, B.J., Skiba, B., Ooms, L.M., Stepto, N., Wu, B., Mitchell, C.A., Tonks, N.K., Watt, M.J., Febbraio, M.A., Crack, P.J., Andrikopoulos, S., Tiganis, T. (2009) Reactive oxygen species enhance insulin sensitivity. Cell Metab. 10(4):260-72. [Pubmed]
- Boivin, B., Zhang S, Arbiser JL, Zhang ZY, Tonks NK. (2008) A modified cysteinyl labeling assay reveals reversible oxidation of protein tyrosine phosphatases in angiomyolipoma cells. Proc Natl Acad Sci U S A. 105(29):9959-64.*Highlighted by The Faculty of 1000. [Pubmed]
- Juarez, J.C., Manuia, M., Burnett, M.E., Betancourt, O., Boivin, B., Shaw, D.E., Tonks, N.K., Mazar, A.P., Doñate, F. (2008) Superoxide dismutase 1 (SOD1) is essential for H2O2-mediated oxidation and inactivation of phosphatases in growth factor signaling. Proc Natl Acad Sci U S A. 105 (20):7147-52 [Pubmed]
- Boivin, B., Lavoie, C., Vaniotis, G., Baragli, A., Villeneuve, L.R., Ethier, N., Trieu, P., Allen, B.G., and Hébert, T.E. (2006) Functional β-adrenergic receptor signalling on nuclear membranes in adult rat and mouse ventricular cardiomyocytes. Cardiovasc. Res. 71, 69-78. * Highlighted by an editorial. [Pubmed]
- Boivin, B., Chevalier, D., Villeneuve, L.R., Rousseau, E., and Allen, B.G. (2003) Functional endothelin receptors are present on nuclei in cardiac ventricular myocytes. J. Biol. Chem. 278, 29153-29163 [Pubmed]
- Pubmed: http://www.ncbi.nlm.nih.gov/pubmed?term=boivin%20b%3B[Author%20Name]
Team members
Dr. Benoit Boivin, Ph.D. Researcher
Dr. Benoit Boivin is a researcher and an assistant professor in the Department of Medicine at the Faculty of Medicine of Université de Montréal. His research at the Montreal Heart Institute Research Centre aims to unravel the molecular mechanisms associated with cardiac hypertrophy. He uses diverse biochemical approaches to specifically study how protein tyrosine phosphatases control the signalling pathways that cause cardiac hypertrophy and heart failure. After receiving his specialized doctorate in Biochemistry from Université de Montréal in 2006 on the organization of the endothelin signal transduction system in ventricular cardiomyocytes, Dr. Boivin continued his training as a postdoctoral fellow at the Cold Spring Harbor Laboratory (CHSL) Cancer Center in suburban New York and worked on the redox regulation of protein tyrosine phosphatases in cancer. His work has been rewarded with many research and equipment grants (Fonds de la recherche du Québec – Santé, Heart and Stroke Foundation of Canada, CHSL Association, Canada Foundation for Innovation). He has also received awards of merit, such as the Jean-Louis Lévesque Award from the Montreal Heart Institute Foundation.
Dominic Melançon, MSc. Research Assistant
Dominic joined the laboratory as a research assistant in July 2012. He is involved in developing molecular, cellular and biochemical tools to characterize protein tyrosine phosphatases and redox signalling in cardiac hypertrophy. He was formerly a research associate in R&D. Through his expertise, he is involved in discovery and development for a therapeutic and diagnostic program for prostate cancer. He was also a research associate in the field of protein chemistry for the vaccinology research unit at the CHUL. He was responsible for developing protein purification methods. Dominic received his bachelor's in Microbiology from Université Laval in 2002 and his master's in Microbiology again from Université Laval in 2003. In his free time, Dominic is an avid runner, and he has run a number of marathons and ultramarathons.
Research projects
Historically, the main function of reactive oxygen species (ROS) has been as an oxidant; ROS therefore cause cellular damage through a process generally called “oxidative stress.” However, we and other research groups have shown that ROS can be involved in physiological and pathophysiological cell signalling by causing the inactivation of protein tyrosine phosphatases (PTPs) in a specific way. The projects in my laboratory aim to elucidate the role of PTPs, which are key regulators in ROS signalling. The members of the PTP family also control many signalling pathways, some of which can lead to cell growth, proliferation, senescence and death. Our work mainly focuses on their role in cardiac pathophysiology.
To date, research on ROS has clarified the role of some signalling networks that control cellular homeostasis in physiological and pathophysiological conditions. ROS are now considered as regulators of many cellular functions (such as migration, autophagy and senescence) and physiological mechanisms (such as vascular tone, glycemia and cardiac hypertrophy).
Phosphorylation is a dynamic and reversible process in which the net phosphorylation of a substrate reflects the coordinated activity of protein kinases that phosphorylize the substrate and protein phosphatases that catalyze the substrate's dephosphorylation. However, in response to extracellular signals, the controlled and localized production of ROS acts as an additional level of control on the signalling of phosphoproteins by regulating the phosphohydrolytic activity of the members of the PTP family.
This regulation of the catalytic activity of PTPs is determined by the architecture of the active site of this family of enzymes, characterized by the signature motif His-Cys-(X)5-Arg-(Ser/Thr) located at the base of the active site cavity, which creates an acidifying environment as it lowers the pKa of catalytic cysteine. This acidifying environment leads to the deprotonation of the side chain of catalytic cysteine into thiolate anions, which makes cysteine an excellent nucleophile for the phosphates of its substrates while making it particularly vulnerable to cellular oxidants (ROS). In other words, the oxidation of catalytic cysteine of specific PTPs neutralizes their catalytic activity and facilitates phosphorylation-dependent signalling.
The nearly one hundred members of the PTP family encoded in the human genome are potentially regulated by the oxidation of their catalytic cysteine to a sulphenic acid. This modification is reversible, and the reduction of inactivated PTPs stops the signal triggered by protein kinases. We have developed a new methodological approach (cysteinyl-labeling assay) that can capture, purify and identify PTPs that have been reversibly oxidized in vivo.
For part of the research in my laboratory, we use this methodological approach to identify the PTPs that are specifically inactivated in a given signalling pathway and that represent a critical control point in the development of cardiac pathologies.
Another more technical focus in my laboratory is to develop new complementary approaches, in collaboration with other laboratories, based on the cysteinyl-labeling assay. The goal of these approaches is to develop specific PTP probes that can be used to: 1) identify oxidized PTPs using mass spectrometry; 2) locate PTP inactivation in the cell through in situ immunofluorescence; and 3) determine the post-translational modifications that reduce PTPs, depending on the cell model and the activated signalling pathway.
Other projects on the role of PTP1B and PTPalpha in the hypertrophic heart are also being developed.
Publications
- Boivin, B., Khairallah, M., Cartier, R. and Allen, B.G. (2012) Characterization of hsp27 kinases activited by elevated aortic pressure in heart. Mol Cell Biochem. 371(1-2):31-42 [Pubmed]
- Boivin, B., Yang, M., Tonks, N.K. (2010) Targeting the reversibly oxidized protein tyrosine phosphatase superfamily. Sci. Signal. 3 (137):pl2 [Pubmed]
- Boivin, B., Tonks, N.K. (2010) Analysis of the redox regulation of protein tyrosine phosphatase superfamily members utilizing a cysteinyl-labeling assay. Methods in Enzymol. 474, 35-50. [Pubmed]
- Loh, K., Deng, H., Fukushima, A., Cai, X., Boivin, B., Galic, S., Bruce, C., Shields, B.J., Skiba, B., Ooms, L.M., Stepto, N., Wu, B., Mitchell, C.A., Tonks, N.K., Watt, M.J., Febbraio, M.A., Crack, P.J., Andrikopoulos, S., Tiganis, T. (2009) Reactive oxygen species enhance insulin sensitivity. Cell Metab. 10(4):260-72. [Pubmed]
- Boivin, B., Zhang S, Arbiser JL, Zhang ZY, Tonks NK. (2008) A modified cysteinyl labeling assay reveals reversible oxidation of protein tyrosine phosphatases in angiomyolipoma cells. Proc Natl Acad Sci U S A. 105(29):9959-64.*Highlighted by The Faculty of 1000. [Pubmed]
- Juarez, J.C., Manuia, M., Burnett, M.E., Betancourt, O., Boivin, B., Shaw, D.E., Tonks, N.K., Mazar, A.P., Doñate, F. (2008) Superoxide dismutase 1 (SOD1) is essential for H2O2-mediated oxidation and inactivation of phosphatases in growth factor signaling. Proc Natl Acad Sci U S A. 105 (20):7147-52 [Pubmed]
- Boivin, B., Lavoie, C., Vaniotis, G., Baragli, A., Villeneuve, L.R., Ethier, N., Trieu, P., Allen, B.G., and Hébert, T.E. (2006) Functional β-adrenergic receptor signalling on nuclear membranes in adult rat and mouse ventricular cardiomyocytes. Cardiovasc. Res. 71, 69-78. * Highlighted by an editorial. [Pubmed]
- Boivin, B., Chevalier, D., Villeneuve, L.R., Rousseau, E., and Allen, B.G. (2003) Functional endothelin receptors are present on nuclei in cardiac ventricular myocytes. J. Biol. Chem. 278, 29153-29163 [Pubmed]
- Pubmed: http://www.ncbi.nlm.nih.gov/pubmed?term=boivin%20b%3B[Author%20Name]