Christophe Ampe | Ghent University (original) (raw)

Papers by Christophe Ampe

Bij bet beeindigen van dit proe fscbrift wens ik een aantal personen welgemeend te bedanken , mij... more Bij bet beeindigen van dit proe fscbrift wens ik een aantal personen welgemeend te bedanken , mijn promotor Joel Vandekerckbove voor zijn bulp, leiding en mot iverende discussies , Marc Van Montagu voor bel ang stelling in de "outsider" van bet labo , Jose Van damme en Magd a Puype voor bulp bij de experiment en en Paul Tempst voor de aangename , jammer genoeg te korte, samenwerking. Verder wens ik nog te bedanken de mensen van het secretariaat voor het verzorgen van typwerk en admini strat ie, de ex 1o de _v erdiepers voor tekeningen , foto's en andere mirakels , Wi lly en Veerle van de mediatbeek, Agnes, Andre , Daniella en Co. voor eeuwi gdurend glasbestand. Ik dank ook "PR" Marc Vanden Bulcke , "grandmaster blot" Guy Bauw en Ann De Clerq voor de aangename momenten in bet labo , het overpoortgenootscbap en de andere mensen van bet labo voor gesprekken en plezier tijdens lunchen ko ffiepauses. Uit eraard dank ik ook mijn zusje, broertjes en Co ., Claudine , Patricia en Kris voor geduld begrip, en vriendschap. Ik ben de firma Plant Genetic Systems zeer erkent elijk voor de financiele steun .

Journal of Biological Chemistry, 1985

The complete amino acid sequence of Acanthamoeba profilin was determined by aligning tryptic, chy... more The complete amino acid sequence of Acanthamoeba profilin was determined by aligning tryptic, chymotryptic, thermolysin, and Staphylococcus aureus V8 protease peptides together with the partial NH2-terminal sequences of the tryptophan-cleavage products. Acanthamoeba profilin contains 125 amino acid residues, is NH2-terminally blocked, and has trimethyllysine at position 103. At five positions in the sequence two amino acids were identified indicating that the amoebae express at least two slightly different profilins. Charged residues are unevenly distributed, the NH2-terminal half being very hydrophobic and the COOH-terminal half being especially rich in basic residues. Comparison of the Acanthamoeba profilin sequence with that of calf spleen profilin (Nystrom, L. E., Lindberg, U., Kendrick-Jones, J., and Jakes, R. (1979) FEBS Lett. 101, 161-165) reveals homology in the NH2-terminal region. We suggest, therefore, that this region participates in the actin-binding activity.

PLOS ONE, Jun 27, 2023

The start phase iso panel in Fig 6A is incorrect as it is an inadvertent duplication of the start... more The start phase iso panel in Fig 6A is incorrect as it is an inadvertent duplication of the start phase veh panel. The updated Fig 6 is provided here in which the start phase iso panel is corrected. The figure legend has been updated to indicate that the experiment presented in Fig 6 was performed independently three times, the images in Fig 6A are taken from one independent experiment, and the results presented in Fig 6B and 6C are from a different independent experiment. The corresponding author confirms that the experimental conditions were identical for the images and data presented in Fig 6A-6C. The raw data underlying the results in Fig 6B and 6C are provided here as S1 File. Representative videos of each condition in Fig 6 are provided in S2 File. Additionally, the corresponding author has shared that, due to an irreparable hard disk failure the raw data underlying all figures except those for Fig 6 and Figure S4 are unavailable.

Journal of Cell Science, Jan 10, 1998

to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was sh... more to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was shown to stimulate actin polymerization at the surface of Listeria (Welch et al., 1997b). This so-called Arp2/3 complex, purified from human platelet extracts, contained two actin-related proteins, Arp2 and Arp3, and five novel proteins, p41-Arc, p34-Arc, p21-Arc, p20-Arc and p16-Arc (Welch et al., 1997a,b). Whether this complex interacts directly with ActA is unknown. In addition to VASP and the Arp2/3 complex, actin-depolymerizing factor (ADF)/cofilin was recently shown to participate in the dynamics of Listeria movement (Carlier et al., 1997; Rosenblatt et al., 1997). In this report, we describe a Listeria affinity approach with bovine brain extracts for identifying protein components in ActA-induced actin tails. Using this method, we have isolated the known components, cofilin, VASP and Arp3, as well as three proteins not previously known to be present in the Listeria actin tails. MATERIALS AND METHODS Brain extracts A fresh bovine brain was cut into pieces and ground by 15 passages in a Dounce homogenizer in an ice-cold extraction buffer (20 mM

Biochemical Journal, Oct 1, 1989

Group-specific chemical modifications of D-xylose isomerase from Streptomyces violaceoruber indic... more Group-specific chemical modifications of D-xylose isomerase from Streptomyces violaceoruber indicated that complete loss of activity is fully correlated with the acylation of a single histidine. Active-site protection, by the ligand combination of xylitol plus Mg2", completely blocked diethyl pyrocarbonate derivatization of this particular residue [Vangrysperre, Callens, Kersters-Hilderson & De Bruyne (1988) Biochem. J. 250, 153-160]. Differential peptide mapping between D-xylose isomerase, which has previously been treated with diethyl pyrocarbonate in the presence or absence of xylitol plus Mg2", allowed specific isolation and sequencing of a peptide containing this active-site histidine. For this purpose we used two essentially new techniques: first, a highly reproducible peptide cleavage protocol for protease-resistant, carbethoxylated proteins with guanidinium hydrochloride as denaturing agent and subtilisin for proteolysis; and second, reverse-phase liquid chromatography with dual-wavelength detection at 214 and 238 nm, and calculation of absorbance ratios. It allowed us to locate the single active-site histidine at position 54 in the primary structure of Streptomyces violaceoruber D-xylose isomerase. The sequence around this residue is conserved in D-xylose isomerases from a diversity of microorganisms , suggesting that this is a structurally and/or functionally essential part of the molecule.

Biological chemistry Hoppe-Seyler, 1986

Chemical Communications, 2021

Furan is used as a caged warhead to covalently target weak protein–protein interactions. Furan-th... more Furan is used as a caged warhead to covalently target weak protein–protein interactions. Furan-thymosin β4 cross-links selectively and irreversibly with actin targeting lysine. Furan technology could be further exploited for covalent drug design.

GigaScience, May 1, 2020

Cell migration research has become a high-content field. However, the quantitative information en... more Cell migration research has become a high-content field. However, the quantitative information encapsulated in these complex and high-dimensional datasets is not fully exploited owing to the diversity of experimental protocols and non-standardized output formats. In addition, typically the datasets are not open for reuse. Making the data open and Findable, Accessible, Interoperable, and Reusable (FAIR) will enable meta-analysis, data integration, and data mining. Standardized data formats and controlled vocabularies are essential for building a suitable infrastructure for that purpose but are not available in the cell migration domain. We here present standardization efforts by the Cell Migration Standardisation Organisation (CMSO), an open community-driven organization to facilitate the development of standards for cell migration data. This work will foster the development of improved algorithms and tools and enable secondary analysis of public datasets, ultimately unlocking new knowledge of the complex biological process of cell migration.

Handbook of experimental pharmacology, 2016

Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous net... more Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.

Journal of Cell Science, Oct 1, 1998

to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was sh... more to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was shown to stimulate actin polymerization at the surface of Listeria (Welch et al., 1997b). This so-called Arp2/3 complex, purified from human platelet extracts, contained two actin-related proteins, Arp2 and Arp3, and five novel proteins, p41-Arc, p34-Arc, p21-Arc, p20-Arc and p16-Arc (Welch et al., 1997a,b). Whether this complex interacts directly with ActA is unknown. In addition to VASP and the Arp2/3 complex, actin-depolymerizing factor (ADF)/cofilin was recently shown to participate in the dynamics of Listeria movement (Carlier et al., 1997; Rosenblatt et al., 1997). In this report, we describe a Listeria affinity approach with bovine brain extracts for identifying protein components in ActA-induced actin tails. Using this method, we have isolated the known components, cofilin, VASP and Arp3, as well as three proteins not previously known to be present in the Listeria actin tails. MATERIALS AND METHODS Brain extracts A fresh bovine brain was cut into pieces and ground by 15 passages in a Dounce homogenizer in an ice-cold extraction buffer (20 mM

Angewandte Chemie, Apr 13, 2023

The G protein‐coupled kisspeptin receptor (GPR54 or KISS1R) is an important mediator in reproduct... more The G protein‐coupled kisspeptin receptor (GPR54 or KISS1R) is an important mediator in reproduction, metabolism and cancer biology; however, there are limited fluorescent probes or antibodies for direct imaging of these receptors in cells and intact tissues, which can help to interrogate their multiple biological roles. Herein, we describe the rational design and characterization of a new acid‐resistant BODIPY‐based amino acid (Trp‐BODIPY PLUS), and its implementation for solid‐phase synthesis of fluorescent bioactive peptides. Trp‐BODIPY PLUS retains the binding capabilities of both short linear and cyclic peptides and displays notable turn‐on fluorescence emission upon target binding for wash‐free imaging. Finally, we employed Trp‐BODIPY PLUS to prepare some of the first fluorogenic kisspeptin‐based probes and visualized the expression and localization of GPR54 receptors in human cells and in whole mouse pancreatic islets by fluorescence imaging.

Bij bet beeindigen van dit proe fscbrift wens ik een aantal personen welgemeend te bedanken , mij... more Bij bet beeindigen van dit proe fscbrift wens ik een aantal personen welgemeend te bedanken , mijn promotor Joel Vandekerckbove voor zijn bulp, leiding en mot iverende discussies , Marc Van Montagu voor bel ang stelling in de "outsider" van bet labo , Jose Van damme en Magd a Puype voor bulp bij de experiment en en Paul Tempst voor de aangename , jammer genoeg te korte, samenwerking. Verder wens ik nog te bedanken de mensen van het secretariaat voor het verzorgen van typwerk en admini strat ie, de ex 1o de _v erdiepers voor tekeningen , foto's en andere mirakels , Wi lly en Veerle van de mediatbeek, Agnes, Andre , Daniella en Co. voor eeuwi gdurend glasbestand. Ik dank ook "PR" Marc Vanden Bulcke , "grandmaster blot" Guy Bauw en Ann De Clerq voor de aangename momenten in bet labo , het overpoortgenootscbap en de andere mensen van bet labo voor gesprekken en plezier tijdens lunchen ko ffiepauses. Uit eraard dank ik ook mijn zusje, broertjes en Co ., Claudine , Patricia en Kris voor geduld begrip, en vriendschap. Ik ben de firma Plant Genetic Systems zeer erkent elijk voor de financiele steun .

Journal of Biological Chemistry, 1985

The complete amino acid sequence of Acanthamoeba profilin was determined by aligning tryptic, chy... more The complete amino acid sequence of Acanthamoeba profilin was determined by aligning tryptic, chymotryptic, thermolysin, and Staphylococcus aureus V8 protease peptides together with the partial NH2-terminal sequences of the tryptophan-cleavage products. Acanthamoeba profilin contains 125 amino acid residues, is NH2-terminally blocked, and has trimethyllysine at position 103. At five positions in the sequence two amino acids were identified indicating that the amoebae express at least two slightly different profilins. Charged residues are unevenly distributed, the NH2-terminal half being very hydrophobic and the COOH-terminal half being especially rich in basic residues. Comparison of the Acanthamoeba profilin sequence with that of calf spleen profilin (Nystrom, L. E., Lindberg, U., Kendrick-Jones, J., and Jakes, R. (1979) FEBS Lett. 101, 161-165) reveals homology in the NH2-terminal region. We suggest, therefore, that this region participates in the actin-binding activity.

PLOS ONE, Jun 27, 2023

The start phase iso panel in Fig 6A is incorrect as it is an inadvertent duplication of the start... more The start phase iso panel in Fig 6A is incorrect as it is an inadvertent duplication of the start phase veh panel. The updated Fig 6 is provided here in which the start phase iso panel is corrected. The figure legend has been updated to indicate that the experiment presented in Fig 6 was performed independently three times, the images in Fig 6A are taken from one independent experiment, and the results presented in Fig 6B and 6C are from a different independent experiment. The corresponding author confirms that the experimental conditions were identical for the images and data presented in Fig 6A-6C. The raw data underlying the results in Fig 6B and 6C are provided here as S1 File. Representative videos of each condition in Fig 6 are provided in S2 File. Additionally, the corresponding author has shared that, due to an irreparable hard disk failure the raw data underlying all figures except those for Fig 6 and Figure S4 are unavailable.

Journal of Cell Science, Jan 10, 1998

to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was sh... more to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was shown to stimulate actin polymerization at the surface of Listeria (Welch et al., 1997b). This so-called Arp2/3 complex, purified from human platelet extracts, contained two actin-related proteins, Arp2 and Arp3, and five novel proteins, p41-Arc, p34-Arc, p21-Arc, p20-Arc and p16-Arc (Welch et al., 1997a,b). Whether this complex interacts directly with ActA is unknown. In addition to VASP and the Arp2/3 complex, actin-depolymerizing factor (ADF)/cofilin was recently shown to participate in the dynamics of Listeria movement (Carlier et al., 1997; Rosenblatt et al., 1997). In this report, we describe a Listeria affinity approach with bovine brain extracts for identifying protein components in ActA-induced actin tails. Using this method, we have isolated the known components, cofilin, VASP and Arp3, as well as three proteins not previously known to be present in the Listeria actin tails. MATERIALS AND METHODS Brain extracts A fresh bovine brain was cut into pieces and ground by 15 passages in a Dounce homogenizer in an ice-cold extraction buffer (20 mM

Biochemical Journal, Oct 1, 1989

Group-specific chemical modifications of D-xylose isomerase from Streptomyces violaceoruber indic... more Group-specific chemical modifications of D-xylose isomerase from Streptomyces violaceoruber indicated that complete loss of activity is fully correlated with the acylation of a single histidine. Active-site protection, by the ligand combination of xylitol plus Mg2", completely blocked diethyl pyrocarbonate derivatization of this particular residue [Vangrysperre, Callens, Kersters-Hilderson & De Bruyne (1988) Biochem. J. 250, 153-160]. Differential peptide mapping between D-xylose isomerase, which has previously been treated with diethyl pyrocarbonate in the presence or absence of xylitol plus Mg2", allowed specific isolation and sequencing of a peptide containing this active-site histidine. For this purpose we used two essentially new techniques: first, a highly reproducible peptide cleavage protocol for protease-resistant, carbethoxylated proteins with guanidinium hydrochloride as denaturing agent and subtilisin for proteolysis; and second, reverse-phase liquid chromatography with dual-wavelength detection at 214 and 238 nm, and calculation of absorbance ratios. It allowed us to locate the single active-site histidine at position 54 in the primary structure of Streptomyces violaceoruber D-xylose isomerase. The sequence around this residue is conserved in D-xylose isomerases from a diversity of microorganisms , suggesting that this is a structurally and/or functionally essential part of the molecule.

Biological chemistry Hoppe-Seyler, 1986

Chemical Communications, 2021

Furan is used as a caged warhead to covalently target weak protein–protein interactions. Furan-th... more Furan is used as a caged warhead to covalently target weak protein–protein interactions. Furan-thymosin β4 cross-links selectively and irreversibly with actin targeting lysine. Furan technology could be further exploited for covalent drug design.

GigaScience, May 1, 2020

Cell migration research has become a high-content field. However, the quantitative information en... more Cell migration research has become a high-content field. However, the quantitative information encapsulated in these complex and high-dimensional datasets is not fully exploited owing to the diversity of experimental protocols and non-standardized output formats. In addition, typically the datasets are not open for reuse. Making the data open and Findable, Accessible, Interoperable, and Reusable (FAIR) will enable meta-analysis, data integration, and data mining. Standardized data formats and controlled vocabularies are essential for building a suitable infrastructure for that purpose but are not available in the cell migration domain. We here present standardization efforts by the Cell Migration Standardisation Organisation (CMSO), an open community-driven organization to facilitate the development of standards for cell migration data. This work will foster the development of improved algorithms and tools and enable secondary analysis of public datasets, ultimately unlocking new knowledge of the complex biological process of cell migration.

Handbook of experimental pharmacology, 2016

Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous net... more Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.

Journal of Cell Science, Oct 1, 1998

to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was sh... more to a previously reported profilin-binding complex in Acanthamoeba (Machesky et al., 1994), was shown to stimulate actin polymerization at the surface of Listeria (Welch et al., 1997b). This so-called Arp2/3 complex, purified from human platelet extracts, contained two actin-related proteins, Arp2 and Arp3, and five novel proteins, p41-Arc, p34-Arc, p21-Arc, p20-Arc and p16-Arc (Welch et al., 1997a,b). Whether this complex interacts directly with ActA is unknown. In addition to VASP and the Arp2/3 complex, actin-depolymerizing factor (ADF)/cofilin was recently shown to participate in the dynamics of Listeria movement (Carlier et al., 1997; Rosenblatt et al., 1997). In this report, we describe a Listeria affinity approach with bovine brain extracts for identifying protein components in ActA-induced actin tails. Using this method, we have isolated the known components, cofilin, VASP and Arp3, as well as three proteins not previously known to be present in the Listeria actin tails. MATERIALS AND METHODS Brain extracts A fresh bovine brain was cut into pieces and ground by 15 passages in a Dounce homogenizer in an ice-cold extraction buffer (20 mM

Angewandte Chemie, Apr 13, 2023

The G protein‐coupled kisspeptin receptor (GPR54 or KISS1R) is an important mediator in reproduct... more The G protein‐coupled kisspeptin receptor (GPR54 or KISS1R) is an important mediator in reproduction, metabolism and cancer biology; however, there are limited fluorescent probes or antibodies for direct imaging of these receptors in cells and intact tissues, which can help to interrogate their multiple biological roles. Herein, we describe the rational design and characterization of a new acid‐resistant BODIPY‐based amino acid (Trp‐BODIPY PLUS), and its implementation for solid‐phase synthesis of fluorescent bioactive peptides. Trp‐BODIPY PLUS retains the binding capabilities of both short linear and cyclic peptides and displays notable turn‐on fluorescence emission upon target binding for wash‐free imaging. Finally, we employed Trp‐BODIPY PLUS to prepare some of the first fluorogenic kisspeptin‐based probes and visualized the expression and localization of GPR54 receptors in human cells and in whole mouse pancreatic islets by fluorescence imaging.