1
|
Remy O, Santin YG, Jonckheere V, Tesseur C, Kaljević J, Van Damme P, Laloux G. Distinct dynamics and proximity networks of hub proteins at the prey-invading cell pole in a predatory bacterium. J Bacteriol 2024; 206:e0001424. [PMID: 38470120 PMCID: PMC11025332 DOI: 10.1128/jb.00014-24] [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: 02/15/2024] [Accepted: 02/23/2024] [Indexed: 03/13/2024] Open
Abstract
In bacteria, cell poles function as subcellular compartments where proteins localize during specific lifecycle stages, orchestrated by polar "hub" proteins. Whereas most described bacteria inherit an "old" pole from the mother cell and a "new" pole from cell division, generating cell asymmetry at birth, non-binary division poses challenges for establishing cell polarity, particularly for daughter cells inheriting only new poles. We investigated polarity dynamics in the obligate predatory bacterium Bdellovibrio bacteriovorus, proliferating through filamentous growth followed by non-binary division within prey bacteria. Monitoring the subcellular localization of two proteins known as polar hubs in other species, RomR and DivIVA, revealed RomR as an early polarity marker in B. bacteriovorus. RomR already marks the future anterior poles of the progeny during the predator's growth phase, during a precise period closely following the onset of divisome assembly and the end of chromosome segregation. In contrast to RomR's stable unipolar localization in the progeny, DivIVA exhibits a dynamic pole-to-pole localization. This behavior changes shortly before the division of the elongated predator cell, where DivIVA accumulates at all septa and both poles. In vivo protein interaction networks for DivIVA and RomR, mapped through endogenous miniTurbo-based proximity labeling, further underscore their distinct roles in cell polarization and reinforce the importance of the anterior "invasive" cell pole in prey-predator interactions. Our work also emphasizes the precise spatiotemporal order of cellular processes underlying B. bacteriovorus proliferation, offering insights into the subcellular organization of bacteria with filamentous growth and non-binary division.IMPORTANCEIn bacteria, cell poles are crucial areas where "hub" proteins orchestrate lifecycle events through interactions with multiple partners at specific times. While most bacteria exhibit one "old" and one "new" pole, inherited from the previous division event, setting polar identity poses challenges in bacteria with non-binary division. This study explores polar proteins in the predatory bacterium Bdellovibrio bacteriovorus, which undergoes filamentous growth followed by non-binary division inside another bacterium. Our research reveals distinct localization dynamics of the polar proteins RomR and DivIVA, highlighting RomR as an early "hub" marking polar identity in the filamentous mother cell. Using miniTurbo-based proximity labeling, we uncovered their unique protein networks. Overall, our work provides new insights into the cell polarity in non-binary dividing bacteria.
Collapse
Affiliation(s)
- Ophélie Remy
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Yoann G. Santin
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Veronique Jonckheere
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Coralie Tesseur
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Jovana Kaljević
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Géraldine Laloux
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| |
Collapse
|
2
|
Chakraborty S, Kanade M, Gayathri P. Mechanism of GTPase activation of a prokaryotic small Ras-like GTPase MglA by an asymmetrically interacting MglB dimer. J Biol Chem 2024; 300:107197. [PMID: 38508314 PMCID: PMC11016934 DOI: 10.1016/j.jbc.2024.107197] [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: 02/03/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024] Open
Abstract
Cell polarity oscillations in Myxococcus xanthus motility are driven by a prokaryotic small Ras-like GTPase, mutual gliding protein A (MglA), which switches from one cell pole to the other in response to extracellular signals. MglA dynamics is regulated by MglB, which functions both as a GTPase activating protein (GAP) and a guanine nucleotide exchange factor (GEF) for MglA. With an aim to dissect the asymmetric role of the two MglB protomers in the dual GAP and GEF activities, we generated a functional MglAB complex by coexpressing MglB with a linked construct of MglA and MglB. This strategy enabled us to generate mutations of individual MglB protomers (MglB1 or MglB2 linked to MglA) and delineate their role in GEF and GAP activities. We establish that the C-terminal helix of MglB1, but not MglB2, stimulates nucleotide exchange through a site away from the nucleotide-binding pocket, confirming an allosteric mechanism. Interaction between the N-terminal β-strand of MglB1 and β0 of MglA is essential for the optimal GEF activity of MglB. Specific residues of MglB2, which interact with Switch-I of MglA, partially contribute to its GAP activity. Thus, the role of the MglB2 protomer in the GAP activity of MglB is limited to restricting the conformation of MglA active site loops. The direct demonstration of the allosteric mechanism of GEF action provides us new insights into the regulation of small Ras-like GTPases, a feature potentially present in many uncharacterized GEFs.
Collapse
Affiliation(s)
- Sukanya Chakraborty
- Department of Biology, Indian Institute of Science Education and Research Pune, Pune, India
| | - Manil Kanade
- Department of Biology, Indian Institute of Science Education and Research Pune, Pune, India
| | - Pananghat Gayathri
- Department of Biology, Indian Institute of Science Education and Research Pune, Pune, India.
| |
Collapse
|
3
|
Chen Y, Topo EJ, Nan B, Chen J. Mathematical modeling of mechanosensitive reversal control in Myxococcus xanthus. Front Microbiol 2024; 14:1294631. [PMID: 38260904 PMCID: PMC10803039 DOI: 10.3389/fmicb.2023.1294631] [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: 09/15/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Adjusting motility patterns according to environmental cues is important for bacterial survival. Myxococcus xanthus, a bacterium moving on surfaces by gliding and twitching mechanisms, modulates the reversal frequency of its front-back polarity in response to mechanical cues like substrate stiffness and cell-cell contact. In this study, we propose that M. xanthus's gliding machinery senses environmental mechanical cues during force generation and modulates cell reversal accordingly. To examine our hypothesis, we expand an existing mathematical model for periodic polarity reversal in M. xanthus, incorporating the experimental data on the intracellular dynamics of the gliding machinery and the interaction between the gliding machinery and a key polarity regulator. The model successfully reproduces the dependence of cell reversal frequency on substrate stiffness observed in M. xanthus gliding. We further propose reversal control networks between the gliding and twitching motility machineries to explain the opposite reversal responses observed in wild type M. xanthus cells that possess both motility mechanisms. These results provide testable predictions for future experimental investigations. In conclusion, our model suggests that the gliding machinery in M. xanthus can function as a mechanosensor, which transduces mechanical cues into a cell reversal signal.
Collapse
Affiliation(s)
- Yirui Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Genetics, Bioinformatics and Computational Biology Graduate Program, Virginia Tech, Blacksburg, VA, United States
| | - Elias J. Topo
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, United States
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, United States
| |
Collapse
|
4
|
Herfurth M, Müller F, Søgaard-Andersen L, Glatter T. A miniTurbo-based proximity labeling protocol to identify conditional protein interactomes in vivo in Myxococcus xanthus. STAR Protoc 2023; 4:102657. [PMID: 37883223 PMCID: PMC10630675 DOI: 10.1016/j.xpro.2023.102657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/05/2023] [Accepted: 09/29/2023] [Indexed: 10/28/2023] Open
Abstract
Protein-protein interactions are foundational for many cellular processes. Such interactions are especially challenging to identify if they are transient or depend on environmental conditions. This protocol details steps to identify stable and transient protein interactomes in the bacterium Myxococcus xanthus using biotin ligase miniTurbo-based proximity labeling. We include instructions for optimizing the expression of control proteins, in vivo biotin labeling of bacteria grown on a surface or in suspension culture, enrichment of biotinylated proteins, and sample processing for proteomic analysis. For complete details on the use and execution of this protocol, please refer to Branon et al. (2018).1.
Collapse
Affiliation(s)
- Marco Herfurth
- Department for Ecophysiology, Max-Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Franziska Müller
- Department for Ecophysiology, Max-Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| | - Lotte Søgaard-Andersen
- Department for Ecophysiology, Max-Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Timo Glatter
- Facility for Proteomics and Mass Spectrometry, Max-Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
| |
Collapse
|
5
|
Han E, Fei C, Alert R, Copenhagen K, Koch MD, Wingreen NS, Shaevitz JW. Local polar order controls mechanical stress and triggers layer formation in developing Myxococcus xanthus colonies. ARXIV 2023:arXiv:2308.00368v1. [PMID: 37576128 PMCID: PMC10418523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Colonies of the social bacterium Myxococcus xanthus go through a morphological transition from a thin colony of cells to three-dimensional droplet-like fruiting bodies as a strategy to survive starvation. The biological pathways that control the decision to form a fruiting body have been studied extensively. However, the mechanical events that trigger the creation of multiple cell layers and give rise to droplet formation remain poorly understood. By measuring cell orientation, velocity, polarity, and force with cell-scale resolution, we reveal a stochastic local polar order in addition to the more obvious nematic order. Average cell velocity and active force at topological defects agree with predictions from active nematic theory, but their fluctuations are anomalously large due to polar active forces generated by the self-propelled rod-shaped cells. We find that M. xanthus cells adjust their reversal frequency to tune the magnitude of this local polar order, which in turn controls the mechanical stresses and triggers layer formation in the colonies.
Collapse
Affiliation(s)
- Endao Han
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Chenyi Fei
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ricard Alert
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstraße 38, 01187 Dresden, Germany
- Center for Systems Biology Dresden, Pfotenhauerstraße 108, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062, Dresden, Germany
| | - Katherine Copenhagen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Matthias D. Koch
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ned S. Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Joshua W. Shaevitz
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
6
|
Carreira LAM, Szadkowski D, Lometto S, Hochberg GKA, Søgaard-Andersen L. Molecular basis and design principles of switchable front-rear polarity and directional migration in Myxococcus xanthus. Nat Commun 2023; 14:4056. [PMID: 37422455 PMCID: PMC10329633 DOI: 10.1038/s41467-023-39773-y] [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: 12/09/2022] [Accepted: 06/28/2023] [Indexed: 07/10/2023] Open
Abstract
During cell migration, front-rear polarity is spatiotemporally regulated; however, the underlying design of regulatory interactions varies. In rod-shaped Myxococcus xanthus cells, a spatial toggle switch dynamically regulates front-rear polarity. The polarity module establishes front-rear polarity by guaranteeing front pole-localization of the small GTPase MglA. Conversely, the Frz chemosensory system, by acting on the polarity module, causes polarity inversions. MglA localization depends on the RomR/RomX GEF and MglB/RomY GAP complexes that localize asymmetrically to the poles by unknown mechanisms. Here, we show that RomR and the MglB and MglC roadblock domain proteins generate a positive feedback by forming a RomR/MglC/MglB complex, thereby establishing the rear pole with high GAP activity that is non-permissive to MglA. MglA at the front engages in negative feedback that breaks the RomR/MglC/MglB positive feedback allosterically, thus ensuring low GAP activity at this pole. These findings unravel the design principles of a system for switchable front-rear polarity.
Collapse
Affiliation(s)
| | - Dobromir Szadkowski
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Stefano Lometto
- Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
- Department of Chemistry and Center for Synthetic Microbiology, Philipps University, 35043, Marburg, Germany
| | - Georg K A Hochberg
- Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
- Department of Chemistry and Center for Synthetic Microbiology, Philipps University, 35043, Marburg, Germany
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
| |
Collapse
|