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Ferro-Gallego P, Vila-Sanjurjo A, Valderrama Pereira AK, Porres Pérez G, Domínguez-Gerpe L. Circular PCR as an efficient and precise umbrella of methods for the generation of circular dsDNA with staggered nicks: Mechanism and types. Biol Methods Protoc 2024; 9:bpae051. [PMID: 39139995 PMCID: PMC11319657 DOI: 10.1093/biomethods/bpae051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 07/11/2024] [Accepted: 07/18/2024] [Indexed: 08/15/2024] Open
Abstract
Here, we introduce the highly versatile circular polymerase chain reaction (CiPCR) technique, propose a mechanism of action, and describe a number of examples demonstrating the versatility of this technique. CiPCR takes place between two fragments of dsDNA with two homologous regions, as long as one of the fragments carries said regions at its 3'- and 5'-ends. Upon hybridization, elongation by a polymerase occurs from all 3'-ends continuously until a 5'-end is reached, leading to stable circular dsDNA with staggered nicks. When both dsDNA fragments carry the homology at their 3'- and 5'-ends (Type I CiPCR), all four 3'-ends effectively prime amplification of the intervening region and CiPCR products can function as template during the reaction. In contrast, when only one of the two dsDNA fragments carries the homologous regions at its 3'- and 5'-ends and the other carries such regions internally (Type II CiPCR), only two 3'-ends can be amplified and CiPCR products possess no template activity. We demonstrate the applicability of both CiPCR types via well-illustrated experimental examples. CiPCR is well adapted to the quick resolution of most of the molecular cloning challenges faced by the biology/biomedicine laboratory, including the generation of insertions, deletions, and mutations.
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Affiliation(s)
- Pedro Ferro-Gallego
- Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain
- Present Address: IBIMA, Instituto de Investigación Biomédica y Plataforma en Nanomedicina, BIONAND, Málaga, 29590, Spain
| | - Antón Vila-Sanjurjo
- Grupo GIBE, Biology Department of the School of Sciences & Interdisciplinary Center for Chemistry and Biology (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Andrea Katherine Valderrama Pereira
- Chemistry Department of the School of Sciences & Interdisciplinary Center for Chemistry and Biology (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Gonzalo Porres Pérez
- Grupo GIBE, Biology Department of the School of Sciences & Interdisciplinary Center for Chemistry and Biology (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Lourdes Domínguez-Gerpe
- Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain
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2
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Weeramange C, Menjivar C, O'Neil PT, El Qaidi S, Harrison KS, Meinhardt S, Bird CL, Sreenivasan S, Hardwidge PR, Fenton AW, Hefty PS, Bose JL, Swint-Kruse L. Fructose-1-kinase has pleiotropic roles in Escherichia coli. J Biol Chem 2024; 300:107352. [PMID: 38723750 PMCID: PMC11157272 DOI: 10.1016/j.jbc.2024.107352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/26/2024] [Accepted: 04/28/2024] [Indexed: 05/21/2024] Open
Abstract
In Escherichia coli, the master transcription regulator catabolite repressor activator (Cra) regulates >100 genes in central metabolism. Cra binding to DNA is allosterically regulated by binding to fructose-1-phosphate (F-1-P), but the only documented source of F-1-P is from the concurrent import and phosphorylation of exogenous fructose. Thus, many have proposed that fructose-1,6-bisphosphate (F-1,6-BP) is also a physiological regulatory ligand. However, the role of F-1,6-BP has been widely debated. Here, we report that the E. coli enzyme fructose-1-kinase (FruK) can carry out its "reverse" reaction under physiological substrate concentrations to generate F-1-P from F-1,6-BP. We further show that FruK directly binds Cra with nanomolar affinity and forms higher order, heterocomplexes. Growth assays with a ΔfruK strain and fruK complementation show that FruK has a broader role in metabolism than fructose catabolism. Since fruK itself is repressed by Cra, these newly-reported events add layers to the dynamic regulation of E. coli's central metabolism that occur in response to changing nutrients. These findings might have wide-spread relevance to other γ-proteobacteria, which conserve both Cra and FruK.
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Affiliation(s)
- Chamitha Weeramange
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Cindy Menjivar
- The Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Pierce T O'Neil
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Kelly S Harrison
- The Department of Molecular Biosciences, The University of Kansas - Lawrence, Lawrence, Kansas, USA
| | - Sarah Meinhardt
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Cole L Bird
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Shwetha Sreenivasan
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Aron W Fenton
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - P Scott Hefty
- College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Jeffrey L Bose
- The Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Liskin Swint-Kruse
- The Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA.
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3
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Weeramange C, Menjivar C, O’Neil PT, El Qaidi S, Harrison KS, Meinhardt S, Bird CL, Sreenivasan S, Hardwidge PR, Fenton AW, Hefty PS, Bose JL, Swint-Kruse L. Fructose-1-kinase has pleiotropic roles in Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.14.571569. [PMID: 38168282 PMCID: PMC10760178 DOI: 10.1101/2023.12.14.571569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
In Escherichia coli, the master transcription regulator Catabolite Repressor Activator (Cra) regulates >100 genes in central metabolism. Cra binding to DNA is allosterically regulated by binding to fructose-1-phosphate (F-1-P), but the only documented source of F-1-P is from the concurrent import and phosphorylation of exogenous fructose. Thus, many have proposed that fructose-1,6-bisphosphate (F-1,6-BP) is also a physiological regulatory ligand. However, the role of F-1,6-BP has been widely debated. Here, we report that the E. coli enzyme fructose-1-kinase (FruK) can carry out its "reverse" reaction under physiological substrate concentrations to generate F-1-P from F-1,6-BP. We further show that FruK directly binds Cra with nanomolar affinity and forms higher order, heterocomplexes. Growth assays with a ΔfruK strain and fruK complementation show that FruK has a broader role in metabolism than fructose catabolism. The ΔfruK strain also alters biofilm formation. Since fruK itself is repressed by Cra, these newly-reported events add layers to the dynamic regulation of E. coli central metabolism that occur in response to changing nutrients. These findings might have wide-spread relevance to other γ-proteobacteria, which conserve both Cra and FruK.
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Affiliation(s)
- Chamitha Weeramange
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Cindy Menjivar
- The Department of Microbiology, Molecular Genetics and Immunology, 3901 Rainbow Blvd, MSN 3029, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Pierce T. O’Neil
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Samir El Qaidi
- College of Veterinary Medicine, 1800 Denison Ave, Kansas State University, Manhattan, KS, USA 66506
| | - Kelly S. Harrison
- The Department of Molecular Biosciences, 2034 Haworth Hall, 1200 Sunnyside Avenue, The University of Kansas – Lawrence, Lawrence, Kansas, USA 66045
| | - Sarah Meinhardt
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Cole L. Bird
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Shwetha Sreenivasan
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Philip R. Hardwidge
- College of Veterinary Medicine, 1800 Denison Ave, Kansas State University, Manhattan, KS, USA 66506
| | - Aron W. Fenton
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - P. Scott Hefty
- College of Veterinary Medicine, 1800 Denison Ave, Kansas State University, Manhattan, KS, USA 66506
| | - Jeffrey L. Bose
- The Department of Microbiology, Molecular Genetics and Immunology, 3901 Rainbow Blvd, MSN 3029, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
| | - Liskin Swint-Kruse
- The Department of Biochemistry and Molecular Biology, 3901 Rainbow Blvd, MSN 3030, The University of Kansas Medical Center, Kansas City, Kansas, USA 66160
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4
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Lethier M, Huard K, Hons M, Favier A, Brutscher B, Boeri Erba E, Abbott DW, Cusack S, Pellegrini E. Structure shows that the BIR2 domain of E3 ligase XIAP binds across the RIPK2 kinase dimer interface. Life Sci Alliance 2023; 6:e202201784. [PMID: 37673444 PMCID: PMC10485824 DOI: 10.26508/lsa.202201784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 08/09/2023] [Accepted: 08/09/2023] [Indexed: 09/08/2023] Open
Abstract
RIPK2 is an essential adaptor for NOD signalling and its kinase domain is a drug target for NOD-related diseases, such as inflammatory bowel disease. However, recent work indicates that the phosphorylation activity of RIPK2 is dispensable for signalling and that inhibitors of both RIPK2 activity and RIPK2 ubiquitination prevent the essential interaction between RIPK2 and the BIR2 domain of XIAP, the key RIPK2 ubiquitin E3 ligase. Moreover, XIAP BIR2 antagonists also block this interaction. To reveal the molecular mechanisms involved, we combined native mass spectrometry, NMR, and cryo-electron microscopy to determine the structure of the RIPK2 kinase BIR2 domain complex and validated the interface with in cellulo assays. The structure shows that BIR2 binds across the RIPK2 kinase antiparallel dimer and provides an explanation for both inhibitory mechanisms. It also highlights why phosphorylation of the kinase activation loop is dispensable for signalling while revealing the structural role of RIPK2-K209 residue in the RIPK2-XIAP BIR2 interaction. Our results clarify the features of the RIPK2 conformation essential for its role as a scaffold protein for ubiquitination.
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Affiliation(s)
- Mathilde Lethier
- https://ror.org/01zjc6908 European Molecular Biology Laboratory, Grenoble, France
| | - Karine Huard
- https://ror.org/01zjc6908 European Molecular Biology Laboratory, Grenoble, France
| | - Michael Hons
- https://ror.org/01zjc6908 European Molecular Biology Laboratory, Grenoble, France
| | - Adrien Favier
- University Grenoble Alpes, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
- CEA, IBS, Grenoble, France
| | - Bernhard Brutscher
- University Grenoble Alpes, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
- CEA, IBS, Grenoble, France
| | - Elisabetta Boeri Erba
- University Grenoble Alpes, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
- CEA, IBS, Grenoble, France
| | - Derek W Abbott
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Stephen Cusack
- https://ror.org/01zjc6908 European Molecular Biology Laboratory, Grenoble, France
| | - Erika Pellegrini
- https://ror.org/01zjc6908 European Molecular Biology Laboratory, Grenoble, France
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5
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Zare-Mehrjerdi O, Trader G, Kirik V. Overlap extension cloning of PCR products into a Gateway-compatible plasmid vector. Biotechniques 2023. [PMID: 37424091 PMCID: PMC10388215 DOI: 10.2144/btn-2023-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023] Open
Abstract
A PCR cloning method that combines a dual selection pGATE-1 plasmid vector and an improved overlap extension cloning was developed. This efficient and cost-effective method allows for the introduction of DNA fragments into the Gateway cloning pipeline. The cloning efficiency is facilitated by a dual selection that includes the ccdB gene and gentamicin resistance. For users of the Gateway cloning system, substantial cost saving comes from eliminating BP recombination and ligation reactions to introduce DNA fragments into pDONR or pENTR vectors. Beyond the Gateway technology, this recombination-based cloning system can be used to efficiently clone PCR amplicons by adding 24-base pair adaptor sequences that are utilized by bacterial homologous recombination mechanism.
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Affiliation(s)
- Omid Zare-Mehrjerdi
- Illinois State University, School of Biological Sciences, Normal, IL 61790-4120, USA
| | - Gracie Trader
- Illinois State University, School of Biological Sciences, Normal, IL 61790-4120, USA
| | - Viktor Kirik
- Illinois State University, School of Biological Sciences, Normal, IL 61790-4120, USA
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6
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Hasan MK, Scott NE, Hays MP, Hardwidge PR, El Qaidi S. Salmonella T3SS effector SseK1 arginine-glycosylates the two-component response regulator OmpR to alter bile salt resistance. Sci Rep 2023; 13:9018. [PMID: 37270573 DOI: 10.1038/s41598-023-36057-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/28/2023] [Indexed: 06/05/2023] Open
Abstract
Type III secretion system (T3SS) effector proteins are primarily recognized for binding host proteins to subvert host immune response during infection. Besides their known host target proteins, several T3SS effectors also interact with endogenous bacterial proteins. Here we demonstrate that the Salmonella T3SS effector glycosyltransferase SseK1 glycosylates the bacterial two-component response regulator OmpR on two arginine residues, R15 and R122. Arg-glycosylation of OmpR results in reduced expression of ompF, a major outer membrane porin gene. Glycosylated OmpR has reduced affinity to the ompF promoter region, as compared to the unglycosylated form of OmpR. Additionally, the Salmonella ΔsseK1 mutant strain had higher bile salt resistance and increased capacity to form biofilms, as compared to WT Salmonella, thus linking OmpR glycosylation to several important aspects of bacterial physiology.
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Affiliation(s)
- Md Kamrul Hasan
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne Within the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000, Australia
| | - Michael P Hays
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | | | - Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA.
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7
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Esmaeilzadeh E, Etemad B, Lavine CL, Garneau L, Li Y, Regan J, Wong C, Sharaf R, Connick E, Volberding P, Sagar M, Seaman MS, Li JZ. Autologous neutralizing antibodies increase with early antiretroviral therapy and shape HIV rebound after treatment interruption. Sci Transl Med 2023; 15:eabq4490. [PMID: 37163616 PMCID: PMC10576978 DOI: 10.1126/scitranslmed.abq4490] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 04/10/2023] [Indexed: 05/12/2023]
Abstract
Early initiation of antiretroviral therapy (ART) alters viral rebound kinetics after analytic treatment interruption (ATI) and may play a role in promoting HIV-1 remission. Autologous neutralizing antibodies (aNAbs) represent a key adaptive immune response in people living with HIV-1. We aimed to investigate the role of aNAbs in shaping post-ATI HIV-1 rebound variants. We performed single-genome amplification of HIV-1 env from pre-ART and post-ATI plasma samples of 12 individuals who initiated ART early after infection. aNAb activity was quantified using pseudoviruses derived from the most common plasma variant, and the serum dilution that inhibited 50% of viral infections was determined. aNAb responses matured while participants were on suppressive ART, because on-ART plasma and purified immunoglobulin G (IgG) demonstrated improved neutralizing activity against pre-ART HIV-1 strains when compared with pre-ART plasma or purified IgG. Post-ATI aNAb responses exerted selective pressure on the rebounding viruses, because the post-ATI HIV-1 strains were more resistant to post-ATI plasma neutralization compared with the pre-ART virus. Several pre-ATI features distinguished post-treatment controllers from noncontrollers, including an infecting HIV-1 sequence that was more similar to consensus HIV-1 subtype B, more restricted proviral diversity, and a stronger aNAb response. Post-treatment control was also associated with the evolution of distinct N-glycosylation profiles in the HIV-1 envelope. In summary, aNAb responses appeared to mature after early initiation of ART and applied selective pressure on rebounding viruses. The combination of aNAb activity with select HIV-1 sequence and reservoir features identified individuals with a greater chance of post-treatment control.
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Affiliation(s)
| | - Behzad Etemad
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Lauren Garneau
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Yijia Li
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - James Regan
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Colline Wong
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Radwa Sharaf
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Paul Volberding
- University of California, San Francisco, San Francisco, CA 94158, USA
| | - Manish Sagar
- Boston University Chobanian and Avedesian School of Medicine, Boston, MA 02118, USA
| | | | - Jonathan Z Li
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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8
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Design of Lactococcus lactis Strains Producing Garvicin A and/or Garvicin Q, Either Alone or Together with Nisin A or Nisin Z and High Antimicrobial Activity against Lactococcus garvieae. Foods 2023; 12:foods12051063. [PMID: 36900581 PMCID: PMC10000435 DOI: 10.3390/foods12051063] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
Lactococcus garvieae is a main ichthyopathogen in rainbow trout (Oncorhynchus mykiss, Walbaum) farming, although bacteriocinogenic L. garvieae with antimicrobial activity against virulent strains of this species have also been identified. Some of the bacteriocins characterized, such as garvicin A (GarA) and garvicin Q (GarQ), may show potential for the control of the virulent L. garvieae in food, feed and other biotechnological applications. In this study, we report on the design of Lactococcus lactis strains that produce the bacteriocins GarA and/or GarQ, either alone or together with nisin A (NisA) or nisin Z (NisZ). Synthetic genes encoding the signal peptide of the lactococcal protein Usp45 (SPusp45), fused to mature GarA (lgnA) and/or mature GarQ (garQ) and their associated immunity genes (lgnI and garI, respectively), were cloned into the protein expression vectors pMG36c, which contains the P32 constitutive promoter, and pNZ8048c, which contains the inducible PnisA promoter. The transformation of recombinant vectors into lactococcal cells allowed for the production of GarA and/or GarQ by L. lactis subsp. cremoris NZ9000 and their co-production with NisA by Lactococcus lactis subsp. lactis DPC5598 and L. lactis subsp. lactis BB24. The strains L. lactis subsp. cremoris WA2-67 (pJFQI), a producer of GarQ and NisZ, and L. lactis subsp. cremoris WA2-67 (pJFQIAI), a producer of GarA, GarQ and NisZ, demonstrated the highest antimicrobial activity (5.1- to 10.7-fold and 17.3- to 68.2-fold, respectively) against virulent L. garvieae strains.
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Identification of a HTT-specific binding motif in DNAJB1 essential for suppression and disaggregation of HTT. Nat Commun 2022; 13:4692. [PMID: 35948542 PMCID: PMC9365803 DOI: 10.1038/s41467-022-32370-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/26/2022] [Indexed: 11/10/2022] Open
Abstract
Huntington’s disease is a neurodegenerative disease caused by an expanded polyQ stretch within Huntingtin (HTT) that renders the protein aggregation-prone, ultimately resulting in the formation of amyloid fibrils. A trimeric chaperone complex composed of Hsc70, DNAJB1 and Apg2 can suppress and reverse the aggregation of HTTExon1Q48. DNAJB1 is the rate-limiting chaperone and we have here identified and characterized the binding interface between DNAJB1 and HTTExon1Q48. DNAJB1 exhibits a HTT binding motif (HBM) in the hinge region between C-terminal domains (CTD) I and II and binds to the polyQ-adjacent proline rich domain (PRD) of soluble as well as aggregated HTT. The PRD of HTT represents an additional binding site for chaperones. Mutation of the highly conserved H244 of the HBM of DNAJB1 completely abrogates the suppression and disaggregation of HTT fibrils by the trimeric chaperone complex. Notably, this mutation does not affect the binding and remodeling of any other protein substrate, suggesting that the HBM of DNAJB1 is a specific interaction site for HTT. Overexpression of wt DNAJB1, but not of DNAJB1H244A can prevent the accumulation of HTTExon1Q97 aggregates in HEK293 cells, thus validating the biological significance of the HBM within DNAJB1. Ayala Mariscal et al have identified and characterized the interface of pathogenic Huntingtin and the molecular chaperone DNAJB1. Histidine-244 of the C-terminal domain of DNAJB1 is a key residues for binding to the poly-proline region of HTT. This binding site is specific for the interaction with Huntingtin.
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10
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El Qaidi S, Scott NE, Hays MP, Hardwidge PR. Arginine glycosylation regulates UDP-GlcNAc biosynthesis in Salmonella enterica. Sci Rep 2022; 12:5293. [PMID: 35351940 PMCID: PMC8964723 DOI: 10.1038/s41598-022-09276-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/21/2022] [Indexed: 12/27/2022] Open
Abstract
The Salmonella enterica SseK1 protein is a type three secretion system effector that glycosylates host proteins during infection on specific arginine residues with N-acetyl glucosamine (GlcNAc). SseK1 also Arg-glycosylates endogenous bacterial proteins and we thus hypothesized that SseK1 activities might be integrated with regulating the intrabacterial abundance of UPD-GlcNAc, the sugar-nucleotide donor used by this effector. After searching for new SseK1 substrates, we found that SseK1 glycosylates arginine residues in the dual repressor-activator protein NagC, leading to increased DNA-binding affinity and enhanced expression of the NagC-regulated genes glmU and glmS. SseK1 also glycosylates arginine residues in GlmR, a protein that enhances GlmS activity. This Arg-glycosylation improves the ability of GlmR to enhance GlmS activity. We also discovered that NagC is a direct activator of glmR expression. Salmonella lacking SseK1 produce significantly reduced amounts of UDP-GlcNAc as compared with Salmonella expressing SseK1. Overall, we conclude that SseK1 up-regulates UDP-GlcNAc synthesis both by enhancing the DNA-binding activity of NagC and by increasing GlmS activity through GlmR glycosylation. Such regulatory activities may have evolved to maintain sufficient levels of UDP-GlcNAc for both bacterial cell wall precursors and for SseK1 to modify other bacterial and host targets in response to environmental changes and during infection.
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Affiliation(s)
- Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne Within the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000, Australia
| | - Michael P Hays
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA.
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11
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Hasan MK, El Qaidi S, Hardwidge PR. The T3SS Effector Protease NleC Is Active within Citrobacter rodentium. Pathogens 2021; 10:pathogens10050589. [PMID: 34065796 PMCID: PMC8151275 DOI: 10.3390/pathogens10050589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/18/2022] Open
Abstract
Whether type III secretion system (T3SS) effector proteins encoded by Gram-negative bacterial pathogens have intra-bacterial activities is an important and emerging area of investigation. Gram-negative bacteria interact with their mammalian hosts by using secretion systems to inject virulence proteins directly into infected host cells. Many of these injected protein effectors are enzymes that modify the structure and inhibit the function of mammalian proteins. The underlying dogma is that T3SS effectors are inactive until they are injected into host cells, where they then fold into their active conformations. We previously observed that the T3SS effectors NleB and SseK1 glycosylate Citrobacter rodentium and Salmonella enterica proteins, respectively, leading to enhanced resistance to environmental stress. Here, we sought to extend these studies to determine whether the T3SS effector protease NleC is also active within C. rodentium. To do this, we expressed the best-characterized mammalian substrate of NleC, the NF-κB p65 subunit in C. rodentium and monitored its proteolytic cleavage as a function of NleC activity. Intra-bacterial p65 cleavage was strictly dependent upon NleC. A p65 mutant lacking the known CE cleavage motif was resistant to NleC. Thus, we conclude that, in addition to NleB, NleC is also enzymatically active within C. rodentium.
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12
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Arginine glycosylation enhances methylglyoxal detoxification. Sci Rep 2021; 11:3834. [PMID: 33589708 PMCID: PMC7884692 DOI: 10.1038/s41598-021-83437-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 01/20/2021] [Indexed: 12/11/2022] Open
Abstract
Type III secretion system effector proteins have primarily been characterized for their interactions with host cell proteins and their ability to disrupt host signaling pathways. We are testing the hypothesis that some effectors are active within the bacterium, where they modulate bacterial signal transduction and physiology. We previously determined that the Citrobacter rodentium effector NleB possesses an intra-bacterial glycosyltransferase activity that increases glutathione synthetase activity to protect the bacterium from oxidative stress. Here we investigated the potential intra-bacterial activities of NleB orthologs in Salmonella enterica and found that SseK1 and SseK3 mediate resistance to methylglyoxal. SseK1 glycosylates specific arginine residues on four proteins involved in methylglyoxal detoxification, namely GloA (R9), GloB (R190), GloC (R160), and YajL (R149). SseK1-mediated Arg-glycosylation of these four proteins significantly enhances their catalytic activity, thus providing another important example of the intra-bacterial activities of type three secretion system effector proteins. These data are also the first demonstration that a Salmonella T3SS effector is active within the bacterium.
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Abstract
Many Gram-negative bacterial pathogens interact with mammalian cells by using type III secretion systems (T3SS) to inject virulence proteins into host cells. A subset of these injected protein 'effectors' are enzymes that inhibit the function of host proteins by catalyzing the addition of unusual post-translational modifications. The E. coli and Citrobacter rodentium NleB effectors, as well as the Salmonella enterica SseK effectors are glycosyltransferases that modify host protein substrates with N-acetyl glucosamine (GlcNAc) on arginine residues. This post-translational modification disrupts the normal functioning of host immune response proteins. T3SS effectors are thought to be inactive within the bacterium and fold into their active conformations after they are injected, due to the activity of chaperones that keep the effectors in a structural state permissive for secretion. While performing mass spectrometry experiments to identify glycosylation substrates of NleB orthologs, we unexpectedly observed that the bacterial glutathione synthetase (GshB) is glycosylated by NleB on arginine residue R256. NleB-mediated glycosylation of GshB resulted in enhanced GshB activity, leading to an increase in glutathione production, and promoted C. rodentium survival in oxidative stress conditions. These data represent, to our knowledge, the first intra-bacterial activity for a T3SS effector and show that arginine-GlcNAcylation, once thought to be restricted to host cell compartments, also plays an important role in regulating bacterial physiology.
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