1
|
Barrows JK, Stubbs KA, Padilla-Montoya IF, Leeper TC, Van Dyke MW. Manganese-dependent transcription regulation by MntR and PerR in Thermus thermophilus HB8. Mol Microbiol 2024; 121:1228-1244. [PMID: 38735869 DOI: 10.1111/mmi.15278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/20/2024] [Accepted: 04/29/2024] [Indexed: 05/14/2024]
Abstract
Bacteria contain conserved mechanisms to control the intracellular levels of metal ions. Metalloregulatory transcription factors bind metal cations and play a central role in regulating gene expression of metal transporters. Often, these transcription factors regulate transcription by binding to a specific DNA sequence in the promoter region of target genes. Understanding the preferred DNA-binding sequence for transcriptional regulators can help uncover novel gene targets and provide insight into the biological role of the transcription factor in the host organism. Here, we identify consensus DNA-binding sequences and subsequent transcription regulatory networks for two metalloregulators from the ferric uptake regulator (FUR) and diphtheria toxin repressor (DtxR) superfamilies in Thermus thermophilus HB8. By homology search, we classify the DtxR homolog as a manganese-specific, MntR (TtMntR), and the FUR homolog as a peroxide-sensing, PerR (TtPerR). Both transcription factors repress separate ZIP transporter genes in vivo, and TtPerR acts as a bifunctional transcription regulator by activating the expression of ferric and hemin transport systems. We show TtPerR and TtMntR bind DNA in the presence of manganese in vitro and in vivo; however, TtPerR is unable to bind DNA in the presence of iron, likely due to iron-mediated histidine oxidation. Unlike canonical PerR homologs, TtPerR does not appear to contribute to peroxide detoxification. Instead, the TtPerR regulon and DNA binding sequence are more reminiscent of Fur or Mur homologs. Collectively, these results highlight the similarities and differences between two metalloregulatory superfamilies and underscore the interplay of manganese and iron in transcription factor regulation.
Collapse
Affiliation(s)
- John K Barrows
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA
| | - Kamya A Stubbs
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA
| | | | - Thomas C Leeper
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA
| | - Michael W Van Dyke
- Department of Chemistry and Biochemistry, Kennesaw State University, Kennesaw, Georgia, USA
| |
Collapse
|
2
|
Jensen GC, Janis MK, Nguyen HN, David OW, Zastrow ML. Fluorescent Protein-Based Sensors for Detecting Essential Metal Ions across the Tree of Life. ACS Sens 2024; 9:1622-1643. [PMID: 38587931 PMCID: PMC11073808 DOI: 10.1021/acssensors.3c02695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Genetically encoded fluorescent metal ion sensors are powerful tools for elucidating metal dynamics in living systems. Over the last 25 years since the first examples of genetically encoded fluorescent protein-based calcium indicators, this toolbox of probes has expanded to include other essential and non-essential metal ions. Collectively, these tools have illuminated fundamental aspects of metal homeostasis and trafficking that are crucial to fields ranging from neurobiology to human nutrition. Despite these advances, much of the application of metal ion sensors remains limited to mammalian cells and tissues and a limited number of essential metals. Applications beyond mammalian systems and in vivo applications in living organisms have primarily used genetically encoded calcium ion sensors. The aim of this Perspective is to provide, with the support of historical and recent literature, an updated and critical view of the design and use of fluorescent protein-based sensors for detecting essential metal ions in various organisms. We highlight the historical progress and achievements with calcium sensors and discuss more recent advances and opportunities for the detection of other essential metal ions. We also discuss outstanding challenges in the field and directions for future studies, including detecting a wider variety of metal ions, developing and implementing a broader spectral range of sensors for multiplexing experiments, and applying sensors to a wider range of single- and multi-species biological systems.
Collapse
Affiliation(s)
- Gary C Jensen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Makena K Janis
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Hazel N Nguyen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Ogonna W David
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Melissa L Zastrow
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| |
Collapse
|
3
|
Rivera J, Valerdi-Negreros JC, Vázquez-Enciso DM, Argueta-Zepeda FS, Vinuesa P. Phylogenomic, structural, and cell biological analyses reveal that Stenotrophomonas maltophilia replicates in acidified Rab7A-positive vacuoles of Acanthamoeba castellanii. Microbiol Spectr 2024; 12:e0298823. [PMID: 38319117 PMCID: PMC10913462 DOI: 10.1128/spectrum.02988-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Acanthamoeba species are clinically relevant free-living amoebae (FLA) ubiquitously found in soil and water bodies. Metabolically active trophozoites graze on diverse microbes via phagocytosis. However, functional studies on Rab GTPases (Rabs), which are critical for controlling vesicle trafficking and maturation, are scarce for this FLA. This knowledge gap can be partly explained by the limited genetic tools available for Acanthamoeba cell biology. Here, we developed plasmids to generate fusions of A. castellanii strain Neff proteins to the N- or C-termini of mEGFP and mCherry2. Phylogenomic and structural analyses of the 11 Neff Rab7 paralogs found in the RefSeq assembly revealed that eight of them had non-canonical sequences. After correcting the gene annotation for the Rab7A ortholog, we generated a line stably expressing an mEGFP-Rab7A fusion, demonstrating its correct localization to acidified macropinocytic and phagocytic vacuoles using fluorescence microscopy live cell imaging (LCI). Direct labeling of live Stenotrophomonas maltophilia ESTM1D_MKCAZ16_6a (Sm18) cells with pHrodo Red, a pH-sensitive dye, demonstrated that they reside within acidified, Rab7A-positive vacuoles. We constructed new mini-Tn7 delivery plasmids and tagged Sm18 with constitutively expressed mScarlet-I. Co-culture experiments of Neff trophozoites with Sm18::mTn7TC1_Pc_mScarlet-I, coupled with LCI and microplate reader assays, demonstrated that Sm18 underwent multiple replication rounds before reaching the extracellular medium via non-lytic exocytosis. We conclude that S. maltophilia belongs to the class of bacteria that can use amoeba as an intracellular replication niche within a Stenotrophomonas-containing vacuole that interacts extensively with the endocytic pathway.IMPORTANCEDiverse Acanthamoeba lineages (genotypes) are of increasing clinical concern, mainly causing amoebic keratitis and granulomatous amebic encephalitis among other infections. S. maltophilia ranks among the top 10 most prevalent multidrug-resistant opportunistic nosocomial pathogens and is a recurrent member of the microbiome hosted by Acanthamoeba and other free-living amoebae. However, little is known about the molecular strategies deployed by Stenotrophomonas for an intracellular lifestyle in amoebae and other professional phagocytes such as macrophages, which allow the bacterium to evade the immune system and the action of antibiotics. Our plasmids and easy-to-use microtiter plate co-culture assays should facilitate investigations into the cellular microbiology of Acanthamoeba interactions with Stenotrophomonas and other opportunistic pathogens, which may ultimately lead to the discovery of new molecular targets and antimicrobial therapies to combat difficult-to-treat infections caused by these ubiquitous microbes.
Collapse
Affiliation(s)
- Javier Rivera
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Julio C. Valerdi-Negreros
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Doctorado en Ciencias Biomédicas, UNAM, Mexico City, Mexico
| | - Diana M. Vázquez-Enciso
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Maestría y Doctorado en Ciencias Bioquímicas, UNAM, Mexico City, Mexico
| | - Fulvia-Stefany Argueta-Zepeda
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Maestría y Doctorado en Ciencias Bioquímicas, UNAM, Mexico City, Mexico
| | - Pablo Vinuesa
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| |
Collapse
|
4
|
He B, Sachla AJ, Helmann JD. TerC proteins function during protein secretion to metalate exoenzymes. Nat Commun 2023; 14:6186. [PMID: 37794032 PMCID: PMC10550928 DOI: 10.1038/s41467-023-41896-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
Collapse
Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - Ankita J Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA.
| |
Collapse
|
5
|
He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536223. [PMID: 37090602 PMCID: PMC10120614 DOI: 10.1101/2023.04.10.536223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn 2+ -dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn 2+ -dependent membrane and extracellular enzymes.
Collapse
Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| |
Collapse
|