- Email: [email protected]
Gary M. Bokoch (1954–2010)
Developmental Cell
Obituary Gary M. Bokoch (1954–2010) Gary Bokoch, an eminent scientist with seminal discoveries in the fields of immunology and signal transduction to his credit, passed away on January 10, 2010. Gary was only 55. Gary is survived by his wife of 32 years, Jan, and two daughters, Jennifer and Rebecca. He was born and grew up in Erie, PA and returned to Erie regularly because he remained close to his family and his native city. Gary attended Pennsylvania State University, earning his B.S. in 1976. He was awarded a Ph.D. in Pharmacology from Vanderbilt University, working in the laboratory of Peter W. Reed. It was here that his life-long interest in leukocyte biology and aspects of cell signaling was sparked. His studies of molecular details of neutrophil activation and reactive oxygen generation are fundamental in the field, and he returned to aspects of these processes throughout his career. His postdoctoral studies in the laboratory of Alfred G. Gilman, at the University of Texas (UT) Southwestern Medical School, were groundbreaking works that included the first purification of the Gi trimer. Working with Toshiaki Katada, and purified pertussis toxin (then called islet activating protein) from Michio Ui’s lab in Japan, Gary showed that it is Gi that is ADP-ribosylated by the pertussis toxin, and later Gary and Toshi succeeded in purifying the Gi trimer (Bokoch et al., 1984) and demonstrating that it is the mediator of ligand-stimulated adenylyl cyclase inhibition, acting very much analogously to Gs and activation of the cyclase, but in response to different receptor-ligand pairs. This work led quickly to far better molecular models for the confusing array of cAMP responses to different agonists and also helped those in the field to realize that there is an even larger family of G proteins, currently numbering >20 alpha subunit genes. After his very productive postdoctoral years, Gary was recruited as Assistant Professor to the Department of Immunology at The Scripps Research Institute in San Diego. There, he discovered his love for Rho GTPases and combined his knowledge of neutrophil biology with small GTPase signaling. With his earlier
experience demonstrating the importance of ADP-ribosylating toxins in identifying important cellular targets, he studied the targets of the botulinum toxin, C3. Working with Suzanne Mumby at UT Southwestern (Bokoch et al., 1988) and Ralph Snyderman at Genentech (Didsbury et al., 1989), Gary soon identified Rho-family GTPases as the relevant targets. These findings soon led to the discovery that one of the GTPases, Rac, regulates the respiratory burst oxidase system in neutrophils—a major milestone in our understanding of the inflammatory response. The discovery that the activity of the GTP-binding protein Rac2 is crucial for initiating the phagocyte oxidative burst, reported by his laboratory in Science (Knaus et al., 1991) and by a British-Israeli group in Nature, paved the way for our understanding of regulatory cellular networks and has shaped our view of NADPH oxidase (Nox) regulation in general. Further publications followed (e.g., see Bokoch et al., 1991), describing novel observations that supported the idea of small GTPases regulating the oxidase on multiple levels. Gary’s interests in GTPases led him to consider other issues of cell biology, in particular how the cytoskeleton is reorganized in response to environmental cues. His group was among the first to
Gary Bokoch. Image courtesy of J. Bokoch.
discern how Rac effectors such as p21activated kinase (Pak) transmit signals to the cytoskeleton. For example, by the early 1990s it was becoming clear that Rac and Rho functions are generally opposed: activated Rac is associated with decreased actin-based stress fibers; activated Rho is associated with increased stress fibers (Bokoch, 2003). With Primal de Lanerolle, Gary showed that Rac, through Pak, inactivates myosin light-chain kinase, leading to loss of stress fibers (Sanders et al., 1999). He later showed that active Rac also directly opposes Rho activation via Pak-mediated phosphorylation of a Rhospecific guanine-nucleotide exchange factor, GEF-H1 (Zenke et al., 2004). These findings helped explain how activation of one GTPase at the cell’s leading edge could affect the activity of other GTPases elsewhere in the cell. His group also discovered a GEF-H1-dependent mechanism for regulating localized RhoA activation during cytokinesis that is under the control of mitotic kinases (Birkenfeld et al., 2007), and, with Gordon Gill’s lab at the University of California, San Diego, showed that Rac affects the cytoskeleton by a different route, namely the inactivation of cofilin by Pak-mediated phosphorylation of LIM kinase (Delorme et al., 2007). An extension of this study led to the discovery of a new cofilin phosphatase, chronophin, which coordinates cofilin activity with the cell cycle. Together, these contributions added greatly to our current models of cytoskeletal regulation. Since 2001 members of the Bokoch laboratory have also been revisiting the Nox enzymes: first, by dissecting the sequence of events enabling electron flow across the plasma membrane during Nox2-mediated superoxide generation. Later, the epithelial oxidase Nox1 sparked Gary’s interest due to its distinct features in concert with conserved principles in Nox biology, such as the importance of oxidase-associated regulatory proteins and of Rac on enzyme activity. These studies culminated in the September 2009 article in Science Signaling (Gianni et al., 2009) that describes a novel regulatory protein in Nox1 signaling, the adaptor Tks. With this paper, published
Developmental Cell 18, March 16, 2010 ª2010 Elsevier Inc. 357
Developmental Cell
Obituary shortly before his untimely passing, Gary had returned to his roots, deciphering the molecular mechanisms of oxidase regulation. Like many of us, Gary grew up as a researcher during the explosive period of GTPase, G protein-coupled receptor, and cell signaling discoveries. Each of us used the emerging techniques and models in GTPase biology and applied them to different systems; in Gary’s case, neutrophil and oxidase biology. At that time, the field was in the thrall of Ras, and strange new relatives such as Rho and Cdc42 were regarded mainly as curiosities. That was soon to change, in no small part due to Gary’s efforts. It was frustrating to have Ras capture most of the attention when so many other GTPases were also coming on line as critical regulators of diverse and essential regulatory pathways. But such frustrations did not stop Gary from co-organizing with Channing Der the first FASEB Summer Research Conference on Low Molecular Weight GTP Binding Proteins in 1991, even when that conference became a regular event and morphed into the ‘‘Ras meeting.’’ At that meeting it quickly became evident that the field was growing rapidly and in many different directions. This led to an impromptu session at the meeting to discuss the nomenclature of what was clearly a large family of GTPases, which was later written up for wider distribution in the FASEB Journal. Gary was the one who regularly persisted in pointing out the value of these small meetings to get together researchers with like interests. This led to many other meetings organized by Gary and even the first FASEB meeting on the Arf GTPases in 2007, which was also inspired by his nagging. He helped to train several people who have gone on to their own successful careers, including Ulla Knaus, Lawrence Quilliam, Thomas Rudel, and Su Dharmawardhane. His concern for others did not stop at his own mentees. A story that illustrates this comes from one of us, who first
met Gary at a FASEB conference. When Gary, who was scheduled to talk about Pak, realized that Jon Chernoff had exciting data in this area but no time slot, Gary volunteered to give up half his own speaker’s allotment to let Jon talk about the cloning of Paks. Being a very young investigator at the time, he did not realize until much later what a generous and unusual gesture that was. This first meeting led to a 15-year collaboration and a lasting friendship. Gary could be something of an enigma to those who did not know him well. And not just because he was a tennis enthusiast despite his office window looking out onto a beautiful fairway of the Torrey Pines golf course. Gary was notable for his deadpan expression and dry sense of humor. Together these often masked a very funny and playful person who could be a pleasure to work and interact with. Members of his laboratory report that pranks around Halloween were the highlight of Gary’s year, and odd items could be found popping up unexpectedly as the holiday approached. But Gary also suffered from serious medical problems his entire adult life and did not want others to know. For example, Gary had a kidney transplant in 1988 and was on an immunosuppressive regimen ever since; a contributing factor in the events that ultimately took his life. Those of us who had some inkling of the toll his medical issues had on his life and personality appreciated both his scientific contributions and humor all the more.
*Correspondence: [email protected] (R.A.K.), [email protected] (U.K.) DOI 10.1016/j.devcel.2010.03.006
Rick Cerione,1 Jonathan Chernoff,2 Richard A. Kahn,3,* and Ulla Knaus4,*
Knaus, U.G., Heyworth, P.G., Evans, T., Curnutte, J.T., and Bokoch, G.M. (1991). Regulation of phagocyte oxygen radical production by the GTP-binding protein Rac 2. Science 254, 1512–1515.
1
Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2 Deputy Scientific Director, Fox Chase Cancer Center, Philadelphia, PA 19111, USA 3 Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA 4 Conway Institute, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland
358 Developmental Cell 18, March 16, 2010 ª2010 Elsevier Inc.
REFERENCES Birkenfeld, J., Nalbant, P., Bohl, B.P., Pertz, O., Hahn, K.M., and Bokoch, G.M. (2007). GEF-H1 modulates localized RhoA activation during cytokinesis under the control of mitotic kinases. Dev. Cell 12, 699–712. Bokoch, G.M. (2003). Biology of the p21-activated kinases. Annu. Rev. Biochem. 72, 743–781. Bokoch, G.M., Katada, T., Northup, J.K., Ui, M., and Gilman, A.G. (1984). Purification and properties of the inhibitory guanine nucleotide-binding regulatory component of adenylate cyclase. J. Biol. Chem. 259, 3560–3567. Bokoch, G.M., Parkos, C.A., and Mumby, S.M. (1988). Purification and characterization of the 22,000-dalton GTP-binding protein substrate for ADP-ribosylation by botulinum toxin, G22K. J. Biol. Chem. 263, 16744–16749. Bokoch, G.M., Quilliam, L.A., Bohl, B.P., Jesaitis, A.J., and Quinn, M.T. (1991). Inhibition of Rap1A binding to cytochrome b558 of NADPH oxidase by phosphorylation of Rap1A. Science 254, 1794–1796. Delorme, V., Machacek, M., DerMardirossian, C., Anderson, K.L., Wittmann, T., Hanein, D., Waterman-Storer, C., Danuser, G., and Bokoch, G.M. (2007). Cofilin activity downstream of Pak1 regulates cell protrusion efficiency by organizing lamellipodium and lamella actin networks. Dev. Cell 13, 646–662. Didsbury, J., Weber, R.F., Bokoch, G.M., Evans, T., and Snyderman, R. (1989). rac, a novel rasrelated family of proteins that are botulinum toxin substrates. J. Biol. Chem. 264, 16378–16382. Gianni, D., Diaz, B., Taulet, N., Fowler, B., Courtneidge, S.A., and Bokoch, G.M. (2009). Novel p47(phox)-related organizers regulate localized NADPH oxidase 1 (Nox1) activity. Sci. Signal. 2, ra54.
Sanders, L.C., Matsumura, F., Bokoch, G.M., and de Lanerolle, P. (1999). Inhibition of myosin light chain kinase by p21-activated kinase. Science 283, 2083–2085. Zenke, F.T., Krendel, M., DerMardirossian, C., King, C.C., Bohl, B.P., and Bokoch, G.M. (2004). p21-activated kinase 1 phosphorylates and regulates 14-3-3 binding to GEF-H1, a microtubulelocalized Rho exchange factor. J. Biol. Chem. 279, 18392–18400.
Obituary Gary M. Bokoch (1954–2010) Gary Bokoch, an eminent scientist with seminal discoveries in the fields of immunology and signal transduction to his credit, passed away on January 10, 2010. Gary was only 55. Gary is survived by his wife of 32 years, Jan, and two daughters, Jennifer and Rebecca. He was born and grew up in Erie, PA and returned to Erie regularly because he remained close to his family and his native city. Gary attended Pennsylvania State University, earning his B.S. in 1976. He was awarded a Ph.D. in Pharmacology from Vanderbilt University, working in the laboratory of Peter W. Reed. It was here that his life-long interest in leukocyte biology and aspects of cell signaling was sparked. His studies of molecular details of neutrophil activation and reactive oxygen generation are fundamental in the field, and he returned to aspects of these processes throughout his career. His postdoctoral studies in the laboratory of Alfred G. Gilman, at the University of Texas (UT) Southwestern Medical School, were groundbreaking works that included the first purification of the Gi trimer. Working with Toshiaki Katada, and purified pertussis toxin (then called islet activating protein) from Michio Ui’s lab in Japan, Gary showed that it is Gi that is ADP-ribosylated by the pertussis toxin, and later Gary and Toshi succeeded in purifying the Gi trimer (Bokoch et al., 1984) and demonstrating that it is the mediator of ligand-stimulated adenylyl cyclase inhibition, acting very much analogously to Gs and activation of the cyclase, but in response to different receptor-ligand pairs. This work led quickly to far better molecular models for the confusing array of cAMP responses to different agonists and also helped those in the field to realize that there is an even larger family of G proteins, currently numbering >20 alpha subunit genes. After his very productive postdoctoral years, Gary was recruited as Assistant Professor to the Department of Immunology at The Scripps Research Institute in San Diego. There, he discovered his love for Rho GTPases and combined his knowledge of neutrophil biology with small GTPase signaling. With his earlier
experience demonstrating the importance of ADP-ribosylating toxins in identifying important cellular targets, he studied the targets of the botulinum toxin, C3. Working with Suzanne Mumby at UT Southwestern (Bokoch et al., 1988) and Ralph Snyderman at Genentech (Didsbury et al., 1989), Gary soon identified Rho-family GTPases as the relevant targets. These findings soon led to the discovery that one of the GTPases, Rac, regulates the respiratory burst oxidase system in neutrophils—a major milestone in our understanding of the inflammatory response. The discovery that the activity of the GTP-binding protein Rac2 is crucial for initiating the phagocyte oxidative burst, reported by his laboratory in Science (Knaus et al., 1991) and by a British-Israeli group in Nature, paved the way for our understanding of regulatory cellular networks and has shaped our view of NADPH oxidase (Nox) regulation in general. Further publications followed (e.g., see Bokoch et al., 1991), describing novel observations that supported the idea of small GTPases regulating the oxidase on multiple levels. Gary’s interests in GTPases led him to consider other issues of cell biology, in particular how the cytoskeleton is reorganized in response to environmental cues. His group was among the first to
Gary Bokoch. Image courtesy of J. Bokoch.
discern how Rac effectors such as p21activated kinase (Pak) transmit signals to the cytoskeleton. For example, by the early 1990s it was becoming clear that Rac and Rho functions are generally opposed: activated Rac is associated with decreased actin-based stress fibers; activated Rho is associated with increased stress fibers (Bokoch, 2003). With Primal de Lanerolle, Gary showed that Rac, through Pak, inactivates myosin light-chain kinase, leading to loss of stress fibers (Sanders et al., 1999). He later showed that active Rac also directly opposes Rho activation via Pak-mediated phosphorylation of a Rhospecific guanine-nucleotide exchange factor, GEF-H1 (Zenke et al., 2004). These findings helped explain how activation of one GTPase at the cell’s leading edge could affect the activity of other GTPases elsewhere in the cell. His group also discovered a GEF-H1-dependent mechanism for regulating localized RhoA activation during cytokinesis that is under the control of mitotic kinases (Birkenfeld et al., 2007), and, with Gordon Gill’s lab at the University of California, San Diego, showed that Rac affects the cytoskeleton by a different route, namely the inactivation of cofilin by Pak-mediated phosphorylation of LIM kinase (Delorme et al., 2007). An extension of this study led to the discovery of a new cofilin phosphatase, chronophin, which coordinates cofilin activity with the cell cycle. Together, these contributions added greatly to our current models of cytoskeletal regulation. Since 2001 members of the Bokoch laboratory have also been revisiting the Nox enzymes: first, by dissecting the sequence of events enabling electron flow across the plasma membrane during Nox2-mediated superoxide generation. Later, the epithelial oxidase Nox1 sparked Gary’s interest due to its distinct features in concert with conserved principles in Nox biology, such as the importance of oxidase-associated regulatory proteins and of Rac on enzyme activity. These studies culminated in the September 2009 article in Science Signaling (Gianni et al., 2009) that describes a novel regulatory protein in Nox1 signaling, the adaptor Tks. With this paper, published
Developmental Cell 18, March 16, 2010 ª2010 Elsevier Inc. 357
Developmental Cell
Obituary shortly before his untimely passing, Gary had returned to his roots, deciphering the molecular mechanisms of oxidase regulation. Like many of us, Gary grew up as a researcher during the explosive period of GTPase, G protein-coupled receptor, and cell signaling discoveries. Each of us used the emerging techniques and models in GTPase biology and applied them to different systems; in Gary’s case, neutrophil and oxidase biology. At that time, the field was in the thrall of Ras, and strange new relatives such as Rho and Cdc42 were regarded mainly as curiosities. That was soon to change, in no small part due to Gary’s efforts. It was frustrating to have Ras capture most of the attention when so many other GTPases were also coming on line as critical regulators of diverse and essential regulatory pathways. But such frustrations did not stop Gary from co-organizing with Channing Der the first FASEB Summer Research Conference on Low Molecular Weight GTP Binding Proteins in 1991, even when that conference became a regular event and morphed into the ‘‘Ras meeting.’’ At that meeting it quickly became evident that the field was growing rapidly and in many different directions. This led to an impromptu session at the meeting to discuss the nomenclature of what was clearly a large family of GTPases, which was later written up for wider distribution in the FASEB Journal. Gary was the one who regularly persisted in pointing out the value of these small meetings to get together researchers with like interests. This led to many other meetings organized by Gary and even the first FASEB meeting on the Arf GTPases in 2007, which was also inspired by his nagging. He helped to train several people who have gone on to their own successful careers, including Ulla Knaus, Lawrence Quilliam, Thomas Rudel, and Su Dharmawardhane. His concern for others did not stop at his own mentees. A story that illustrates this comes from one of us, who first
met Gary at a FASEB conference. When Gary, who was scheduled to talk about Pak, realized that Jon Chernoff had exciting data in this area but no time slot, Gary volunteered to give up half his own speaker’s allotment to let Jon talk about the cloning of Paks. Being a very young investigator at the time, he did not realize until much later what a generous and unusual gesture that was. This first meeting led to a 15-year collaboration and a lasting friendship. Gary could be something of an enigma to those who did not know him well. And not just because he was a tennis enthusiast despite his office window looking out onto a beautiful fairway of the Torrey Pines golf course. Gary was notable for his deadpan expression and dry sense of humor. Together these often masked a very funny and playful person who could be a pleasure to work and interact with. Members of his laboratory report that pranks around Halloween were the highlight of Gary’s year, and odd items could be found popping up unexpectedly as the holiday approached. But Gary also suffered from serious medical problems his entire adult life and did not want others to know. For example, Gary had a kidney transplant in 1988 and was on an immunosuppressive regimen ever since; a contributing factor in the events that ultimately took his life. Those of us who had some inkling of the toll his medical issues had on his life and personality appreciated both his scientific contributions and humor all the more.
*Correspondence: [email protected] (R.A.K.), [email protected] (U.K.) DOI 10.1016/j.devcel.2010.03.006
Rick Cerione,1 Jonathan Chernoff,2 Richard A. Kahn,3,* and Ulla Knaus4,*
Knaus, U.G., Heyworth, P.G., Evans, T., Curnutte, J.T., and Bokoch, G.M. (1991). Regulation of phagocyte oxygen radical production by the GTP-binding protein Rac 2. Science 254, 1512–1515.
1
Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2 Deputy Scientific Director, Fox Chase Cancer Center, Philadelphia, PA 19111, USA 3 Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA 4 Conway Institute, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland
358 Developmental Cell 18, March 16, 2010 ª2010 Elsevier Inc.
REFERENCES Birkenfeld, J., Nalbant, P., Bohl, B.P., Pertz, O., Hahn, K.M., and Bokoch, G.M. (2007). GEF-H1 modulates localized RhoA activation during cytokinesis under the control of mitotic kinases. Dev. Cell 12, 699–712. Bokoch, G.M. (2003). Biology of the p21-activated kinases. Annu. Rev. Biochem. 72, 743–781. Bokoch, G.M., Katada, T., Northup, J.K., Ui, M., and Gilman, A.G. (1984). Purification and properties of the inhibitory guanine nucleotide-binding regulatory component of adenylate cyclase. J. Biol. Chem. 259, 3560–3567. Bokoch, G.M., Parkos, C.A., and Mumby, S.M. (1988). Purification and characterization of the 22,000-dalton GTP-binding protein substrate for ADP-ribosylation by botulinum toxin, G22K. J. Biol. Chem. 263, 16744–16749. Bokoch, G.M., Quilliam, L.A., Bohl, B.P., Jesaitis, A.J., and Quinn, M.T. (1991). Inhibition of Rap1A binding to cytochrome b558 of NADPH oxidase by phosphorylation of Rap1A. Science 254, 1794–1796. Delorme, V., Machacek, M., DerMardirossian, C., Anderson, K.L., Wittmann, T., Hanein, D., Waterman-Storer, C., Danuser, G., and Bokoch, G.M. (2007). Cofilin activity downstream of Pak1 regulates cell protrusion efficiency by organizing lamellipodium and lamella actin networks. Dev. Cell 13, 646–662. Didsbury, J., Weber, R.F., Bokoch, G.M., Evans, T., and Snyderman, R. (1989). rac, a novel rasrelated family of proteins that are botulinum toxin substrates. J. Biol. Chem. 264, 16378–16382. Gianni, D., Diaz, B., Taulet, N., Fowler, B., Courtneidge, S.A., and Bokoch, G.M. (2009). Novel p47(phox)-related organizers regulate localized NADPH oxidase 1 (Nox1) activity. Sci. Signal. 2, ra54.
Sanders, L.C., Matsumura, F., Bokoch, G.M., and de Lanerolle, P. (1999). Inhibition of myosin light chain kinase by p21-activated kinase. Science 283, 2083–2085. Zenke, F.T., Krendel, M., DerMardirossian, C., King, C.C., Bohl, B.P., and Bokoch, G.M. (2004). p21-activated kinase 1 phosphorylates and regulates 14-3-3 binding to GEF-H1, a microtubulelocalized Rho exchange factor. J. Biol. Chem. 279, 18392–18400.