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Leysen S, Van Herreweghe JM, Callewaert L, Heirbaut M, Buntinx P, Michiels CW, Strelkov SV. Molecular basis of bacterial defense against host lysozymes: X-ray structures of periplasmic lysozyme inhibitors PliI and PliC. J Mol Biol 2010; 405:1233-45. [PMID: 21146533 DOI: 10.1016/j.jmb.2010.12.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/25/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
Abstract
Lysozymes play a key role in the innate immune system of vertebrates and invertebrates by hydrolyzing peptidoglycan, a vital component of the bacterial cell wall. Gram-negative bacteria produce various types of lysozyme inhibitors that allow them to survive the bactericidal action of lysozyme when their outer membrane is permeabilized. So far, three lysozyme inhibitor families have been described: the Ivy (inhibitor of vertebrate lysozyme) family, the MliC/PliC (membrane-associated/periplasmic lysozyme inhibitor of C-type lysozyme) family, and the PliI (periplasmic lysozyme inhibitor of I-type lysozyme) family. Here, we report high-resolution crystal structures of Salmonella typhimurium PliC (PliC-St) and Aeromonas hydrophila PliI (PliI-Ah). The structure of PliI-Ah is the first in the recently discovered PliI family of lysozyme inhibitors, while the structure of PliC-St is the first structure of a periplasmic lysozyme inhibitor from the PliC/MliC family. Using small-angle X-ray scattering, we demonstrate that both PliC-St and PliI-Ah form stable dimers in solution. The functional dimer architecture of PliC-St is very different from that of the recently described MliC from Pseudomonas aeruginosa (MliC-Pa), despite the close resemblance of their monomers. Furthermore, PliI-Ah has distinctly different monomer and dimer folds compared to PliC, MliC, and Ivy proteins. Site-directed mutagenesis suggests that the inhibitory action of PliI-Ah proceeds via an insertion of a loop containing the conserved SGxY motif into the active center of I-type lysozymes. This motif is related to the functional SGxxY motif found in the MliC/PliC family.
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Affiliation(s)
- S Leysen
- Laboratory for Biocrystallography, Department of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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Vanderkelen L, Van Herreweghe JM, Vanoirbeek KGA, Baggerman G, Myrnes B, Declerck PJ, Nilsen IW, Michiels CW, Callewaert L. Identification of a bacterial inhibitor against g-type lysozyme. Cell Mol Life Sci 2010; 68:1053-64. [PMID: 20734102 DOI: 10.1007/s00018-010-0507-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/12/2010] [Accepted: 08/10/2010] [Indexed: 01/17/2023]
Abstract
Lysozymes are antibacterial effectors of the innate immune system in animals that hydrolyze peptidoglycan. Bacteria have evolved protective mechanisms that contribute to lysozyme tolerance such as the production of lysozyme inhibitors, but only inhibitors of chicken (c-) and invertebrate (i-) type lysozyme have been identified. We here report the discovery of a novel Escherichia coli inhibitor specific for goose (g-) type lysozymes, which we designate PliG (periplasmic lysozyme inhibitor of g-type lysozyme). Although it does not inhibit c- or i-type lysozymes, PliG shares a structural sequence motif with the previously described PliI and MliC/PliC lysozyme inhibitor families, suggesting a common ancestry and mode of action. Deletion of pliG increased the sensitivity of E. coli to g-type lysozyme. The existence of inhibitors against all major types of animal lysozyme and their contribution to lysozyme tolerance suggest that lysozyme inhibitors may play a role in bacterial interactions with animal hosts.
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Affiliation(s)
- L Vanderkelen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre, Katholieke Universiteit Leuven, Belgium
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Zuccarello D, Ferlin A, Vinanzi C, Prana E, Garolla A, Callewaert L, Claessens F, Brinkmann AO, Foresta C. Detailed functional studies on androgen receptor mild mutations demonstrate their association with male infertility. Clin Endocrinol (Oxf) 2008; 68:580-8. [PMID: 17970778 DOI: 10.1111/j.1365-2265.2007.03069.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONTEXT Mutations in the androgen receptor (AR) gene can cause the androgen insensitivity syndrome (AIS). For complete and severe partial AIS, well-characterized in vitro functional assays can be used for genotype-phenotype correlation; however, for mild forms of AIS, as associated with male infertility, experimental evidence is scarce or lacking. In particular, optimal in vitro functional tests informative about the genotype-phenotype relation have not been described. OBJECTIVE The objective of this study was to investigate the association among genotype and phenotype for AR mutations found in infertile males by conventional functional assays and additional in-depth studies performed with several gene reporters. DESIGN To this aim, we selected four AR missense mutations associated with isolated male infertility (L547F and two novel mutations A474V and S650G) or partial AIS (Y571H). After introduction of the specific mutations in AR expression plasmid, we performed classical in vitro studies (Western immunoblotting, electrophoretic mobility shift assay, hormone-response curves) and transactivation assays with different reporter constructs (MMTV, Sc-ARU-TK, TAT-GRE- 2X, Slp-ARU-TK and PEM). RESULTS AND CONCLUSIONS Our results showed that standard functional tests provide sufficient information only for severe AR mutations, whereas for AR mutations found in mild AIS patients with male infertility, only an extensive analysis with different in vitro systems, and in particular with PEM promoter, can give information on the functionality of the AR and therefore on the pathogenicity of the mutations and on genotype-phenotype correlation.
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Affiliation(s)
- D Zuccarello
- Department of Histology, Microbiology and Medical Biotechnology, University of Padova, Italy
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Vanderkelen L, Callewaert L, Van Herreweghe J, Aertsen A, Michiels CW. Identification of a bacterial inhibitor of G-type lysozyme. Commun Agric Appl Biol Sci 2008; 73:227-230. [PMID: 18831280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- L Vanderkelen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre, Department of Microbial and Molecular Systems, Katholieke Universiteit Leuven, Kasteelpark Arenberg, BE-3001 Leuven, Belgium
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Van Herreweghe JM, Vanderkelen L, Callewaert L, Aertsen A, Michiels CW. Isolation of a bacterial inhibitor of the invertebrate type lysozyme. Commun Agric Appl Biol Sci 2008; 73:237-241. [PMID: 18831282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- J M Van Herreweghe
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre, Department of Microbial and Molecular Systems, Katholieke Universiteit Leuven, Kasteelpark Arenberg, BE-3001 Heverlee, Belgium
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Verrijdt G, Tanner T, Moehren U, Callewaert L, Haelens A, Claessens F. The androgen receptor DNA-binding domain determines androgen selectivity of transcriptional response. Biochem Soc Trans 2007; 34:1089-94. [PMID: 17073757 DOI: 10.1042/bst0341089] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The AR (androgen receptor) is a hormone-dependent transcription factor that translates circulating androgen hormone levels into a physiological cellular response by directly regulating the expression of its target genes. It is the key molecule in e.g. the development and maintenance of the male sexual characteristics, spermatocyte production and prostate gland development and growth. It is also a major factor in the onset and maintenance of prostate cancer and a first target for pharmaceutical action against the further proliferation of prostate cancer cells. The AR is a member of the steroid hormone receptors, a group of steroid-inducible transcription factors sharing an identical consensus DNA-binding motif. The problem of how specificity in gene activation is achieved among the different members of this nuclear receptor subfamily is still unclear. In this report, we describe our investigations on how the AR can specifically activate its target genes, while the other steroid hormone receptors do not, despite having the same consensus monomeric DNA-binding motif. In this respect, we describe how the AR interacts with a newly identified class of steroid-response elements to which only the AR and not, for example, the glucocorticoid receptor can bind.
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Affiliation(s)
- G Verrijdt
- Laboratory of Molecular Endocrinology, Division of Biochemistry, Campus Gasthuisberg O and N1, Catholic University of Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Claessens F, Verrijdt G, Haelens A, Callewaert L, Moehren U, d'Alesio A, Tanner T, Schauwaers K, Denayer S, Van Tilborgh N. Molecular biology of the androgen responses. Andrologia 2006; 37:209-10. [PMID: 16336250 DOI: 10.1111/j.1439-0272.2005.00698.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- F Claessens
- Molecular Endocrinology Laboratory, Faculty of Medicine, K.U. Leuven, Belgium
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Deckers D, Aertsen A, Callewaert L, Michiels CW. Role of lysozyme inhbitors in bacterial colonization of egg albumen. Commun Agric Appl Biol Sci 2006; 71:7-10. [PMID: 17191463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- D Deckers
- Laboratory of Food Microbiology, Kasteelpark Arenberg 22, BE-3001 Leuven, Belgium
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Callewaert L, Masschalck B, Aertsen A, Michiels CW. Detection and isolation method for bacterial lysozyme inhibitors by use of lysozyme affinity chromatography. Commun Agric Appl Biol Sci 2005; 70:73-7. [PMID: 16366278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- L Callewaert
- Laboratory of Food Microbiology, Katholieke Universiteit Leuven, Belgium
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Deckers D, Masschalck B, Aertsen A, Callewaert L, Van Tiggelen CGM, Atanassova M, Michiels CW. Periplasmic lysozyme inhibitor contributes to lysozyme resistance in Escherichia coli. Cell Mol Life Sci 2004; 61:1229-37. [PMID: 15141308 DOI: 10.1007/s00018-004-4066-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The product of the Escherichia coli ORFan gene ykfE was recently shown to be a strong inhibitor of C-type lysozyme in vitro. The gene was correspondingly renamed ivy (inhibitor of vertebrate lysozyme), but its biological function in E. coli remains unknown. In this work, we investigated the role of Ivy in the resistance of E. coli to the bactericidal effect of lysozyme in the presence of outer-membrane-permeabilizing treatments. Both in the presence of lactoferrin (3.0 mg/ml) and under high hydrostatic pressure (250 MPa), the lysozyme resistance of E. coli MG1655 was decreased by knock-out of Ivy, and increased by overexpression of Ivy. However, knock-out of Ivy did not increase the lysozyme sensitivity of an E. coli MG1655 mutant previously described to be resistant to lysozyme under high pressure. These results indicate that Ivy is one of several factors that affect lysozyme resistance in E. coli, and suggest a possible function for Ivy as a host interaction factor in commensal and pathogenic E. coli.
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Affiliation(s)
- D Deckers
- Laboratory of Food Microbiology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
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Callewaert L, Verrijdt G, Haelens A, Claessens F. Differential Effect of Small Ubiquitin-Like Modifier (SUMO)-ylation of the Androgen Receptor in the Control of Cooperativity on SelectiveVersusCanonical Response Elements. Mol Endocrinol 2004; 18:1438-49. [PMID: 15031320 DOI: 10.1210/me.2003-0313] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The androgen receptor (AR) can be small ubiquitin-like modifier (SUMO)-ylated in its amino-terminal domain at lysines 385 and 511. This SUMO-ylation is responsive to several agonists, but is not induced by the pure antagonist hydroxyflutamide. We show that the main site of interaction of Ubc9, the SUMO-1 conjugating enzyme, resides in transcription activation unit 5. Overexpression of SUMO-1 represses the AR-mediated transcription, and this effect is abolished after mutating both SUMO-1 acceptor sites. On the other hand, the mutation of lysine 385 clearly affects the cooperativity of the receptor on multiple hormone response elements. Lysine 511 is not implicated in this function. Surprisingly, these effects on cooperativity clearly depend on the nature of the response elements. When selective androgen response elements, which are organized as direct repeats of 5'-TGTTCT-3'-like sequences, were tested, the lysine 385 mutation did not increase the androgen response. Point mutations changing the direct-repeat elements into inverted-repeat elements restored the effects of the lysine 385 mutation on cooperativity. In conclusion, SUMO-ylation of the AR might have a differential function in the control of cooperativity, depending on the conformation of the AR dimer bound to DNA.
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Affiliation(s)
- L Callewaert
- Division of Biochemistry, Faculty of Medicine, University of Leuven, Leuven, Belgium
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Breyne P, Dreesen R, Vandepoele K, De Veylder L, Van Breusegem F, Callewaert L, Rombauts S, Raes J, Cannoot B, Engler G, Inzé D, Zabeau M. Transcriptome analysis during cell division in plants. Proc Natl Acad Sci U S A 2002; 99:14825-30. [PMID: 12393816 PMCID: PMC137503 DOI: 10.1073/pnas.222561199] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2002] [Accepted: 09/16/2002] [Indexed: 11/18/2022] Open
Abstract
Using synchronized tobacco Bright Yellow-2 cells and cDNA-amplified fragment length polymorphism-based genomewide expression analysis, we built a comprehensive collection of plant cell cycle-modulated genes. Approximately 1,340 periodically expressed genes were identified, including known cell cycle control genes as well as numerous unique candidate regulatory genes. A number of plant-specific genes were found to be cell cycle modulated. Other transcript tags were derived from unknown plant genes showing homology to cell cycle-regulatory genes of other organisms. Many of the genes encode novel or uncharacterized proteins, indicating that several processes underlying cell division are still largely unknown.
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Affiliation(s)
- Peter Breyne
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L. Ledeganckstraat 35, Belgium
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Haelens A, Verrijdt G, Callewaert L, Peeters B, Rombauts W, Claessens F. Androgen-receptor-specific DNA binding to an element in the first exon of the human secretory component gene. Biochem J 2001; 353:611-20. [PMID: 11171058 PMCID: PMC1221607 DOI: 10.1042/0264-6021:3530611] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Androgens and glucocorticoids are steroid hormones, which exert their effects in vivo by binding and activating their cognate receptors. These intracellular receptors are transcription factors that can bind specific DNA sequences, called hormone response elements, located near the target genes. Although the androgen receptor (AR) and the glucocorticoid receptor (GR) bind the same consensus DNA sequence, androgen-specific responses can be achieved by non-conventional androgen response elements (AREs). Here we determine the specificity mechanism of such a selective element recently identified in the first exon of the human gene for secretory component (sc ARE). This sc ARE consists of two receptor-binding hexamers separated by three nucleotides. The DNA-binding domains of the AR and GR both bind the sc ARE, but, although the AR fragment dimerizes on the element, the GR fragment does not. Comparing the affinities of the DNA-binding domains for mutant forms of the sc ARE revealed that dimeric GR binding is actively excluded by the left hexamer and more precisely by the presence of a G residue at position -3, relative to the central spacer nucleotide. Inserting a G at this position changed a non-selective element into an androgen-selective one. We postulate that the AR recognizes the sc ARE as a direct repeat of two 5'-TGTTCT-3'-like core sequences instead of the classical inverted repeat. Direct repeat binding is not possible for the GR, thus explaining the selectivity of the sc ARE. This alternative dimerization by the AR on the sc ARE is also indicated by the DNA-binding characteristics of receptor fragments in which the dimerization interfaces were swapped. In addition, the flanking and spacer sequences seem to affect the functionality of the sc ARE.
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Affiliation(s)
- A Haelens
- Division of Biochemistry, Faculty of Medicine, Campus Gasthuisberg, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Callewaert L, Puers B, Sansen W, Jarvis JC, Salmons S. Programmable implantable device for investigating the adaptive response of skeletal muscle to chronic electrical stimulation. Med Biol Eng Comput 1992. [DOI: 10.1007/bf02446124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Callewaert L, Puers B, Sansen W, Jarvis JC, Salmons S. Programmable implantable device for investigating the adaptive response of skeletal muscle to chronic electrical stimulation. Med Biol Eng Comput 1991; 29:548-53. [PMID: 1817220 DOI: 10.1007/bf02442329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- L Callewaert
- Departement Elektrotechniek, Afd. ESAT-MICAS, Katholieke Universiteit Leuven, Heverlee, Belgium
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Eychmans W, Callewaert L, Steyaert M, Sansen W. The Internal Human Conditioning System: a multipurpose programmable biomedical system. J Med Eng Technol 1989; 13:93-5. [PMID: 2733019 DOI: 10.3109/03091908909030204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A proposed general-purpose implantable biomedical system is described. This Internal Human Conditioning System (IHCS) is capable of measuring biomedical data of various kinds on a number of independent input channels. The number and specifications of these channels are software selectable by means of a low-power microprocessor. The system is also equipped with different programmable stimulation devices. These stimulators can deliver a programmable waveform in order to stimulate a specific muscle or to carry out an impedance measurement. The on-board eight bit microprocessor is used for communication with the outside world, by means of a serial link. The processor used is the 68HC11 from Motorola. By extensive use of the processor's 'sleep' mode and by switching off all unnecessary electronics, the amount of power consumed is drastically reduced. At present, a two-channel input chip and a programmable stimulator chip have been developed so that a complete system can be produced. For the sake of illustration, some realized and possible future applications are discussed.
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Affiliation(s)
- W Eychmans
- Katholieke Universiteit Leuven, Department Electrotechniek, Belgium
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