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Porter KJ, Cao L, Osteryoung KW. Dynamics of the Synechococcus elongatus cytoskeletal GTPase FtsZ yields mechanistic and evolutionary insight into cyanobacterial and chloroplast FtsZs. J Biol Chem 2023; 299:102917. [PMID: 36657643 PMCID: PMC9975276 DOI: 10.1016/j.jbc.2023.102917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/17/2023] Open
Abstract
The division of cyanobacteria and their chloroplast descendants is orchestrated by filamenting temperature-sensitive Z (FtsZ), a cytoskeletal GTPase that polymerizes into protofilaments that form a "Z ring" at the division site. The Z ring has both a scaffolding function for division-complex assembly and a GTPase-dependent contractile function that drives cell or organelle constriction. A single FtsZ performs these functions in bacteria, whereas in chloroplasts, they are performed by two copolymerizing FtsZs, called AtFtsZ2 and AtFtsZ1 in Arabidopsis thaliana, which promote protofilament stability and dynamics, respectively. To probe the differences between cyanobacterial and chloroplast FtsZs, we used light scattering to characterize the in vitro protofilament dynamics of FtsZ from the cyanobacterium Synechococcus elongatus PCC 7942 (SeFtsZ) and investigate how coassembly of AtFtsZ2 or AtFtsZ1 with SeFtsZ influences overall dynamics. SeFtsZ protofilaments assembled rapidly and began disassembling before GTP depletion, whereas AtFtsZ2 protofilaments were far more stable, persisting beyond GTP depletion. Coassembled SeFtsZ-AtFtsZ2 protofilaments began disassembling before GTP depletion, similar to SeFtsZ. In contrast, AtFtsZ1 did not alter disassembly onset when coassembled with SeFtsZ, but fluorescence recovery after photobleaching analysis showed it increased the turnover of SeFtsZ subunits from SeFtsZ-AtFtsZ1 protofilaments, mirroring its effect upon coassembly with AtFtsZ2. Comparisons of our findings with previous work revealed consistent differences between cyanobacterial and chloroplast FtsZ dynamics and suggest that the scaffolding and dynamics-promoting functions were partially separated during evolution of two chloroplast FtsZs from their cyanobacterial predecessor. They also suggest that chloroplasts may have evolved a mechanism distinct from that in cyanobacteria for promoting FtsZ protofilament dynamics.
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Affiliation(s)
- Katie J Porter
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Lingyan Cao
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
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2
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Qi X, Chen S, Wang H, Feng J, Chen H, Qin Z, Deng Y. Comparative physiology and transcriptome analysis reveals that chloroplast development influences silver-white leaf color formation in Hydrangea macrophylla var. maculata. BMC PLANT BIOLOGY 2022; 22:345. [PMID: 35842592 PMCID: PMC9287875 DOI: 10.1186/s12870-022-03727-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Hydrangea macrophylla var. Maculata 'Yinbianxiuqiu' (YB) is an excellent plant species with beautiful flowers and leaves with silvery white edges. However, there are few reports on its leaf color characteristics and color formation mechanism. RESULTS The present study compared the phenotypic, physiological and transcriptomic differences between YB and a full-green leaf mutant (YM) obtained from YB. The results showed that YB and YM had similar genetic backgrounds, but photosynthesis was reduced in YB. The contents of pigments were significantly decreased at the edges of YB leaves compared to YM leaves. The ultrastructure of chloroplasts in the YB leaves was irregular. Transcriptome profiling identified 7,023 differentially expressed genes between YB and YM. The expression levels of genes involved in photosynthesis, chloroplast development and division were different between YB and YM. Quantitative real-time PCR showed that the expression trends were generally consistent with the transcriptome data. CONCLUSIONS Taken together, the formation of the silvery white leaf color of H. macrophylla var. maculata was primarily due to the abnormal development of chloroplasts. This study facilitates the molecular function analysis of key genes involved in chloroplast development and provides new insights into the molecular mechanisms involved in leaf coloration in H. macrophylla.
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Affiliation(s)
- Xiangyu Qi
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Shuangshuang Chen
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Huadi Wang
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, 212013, China
| | - Jing Feng
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Huijie Chen
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Ziyi Qin
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Yanming Deng
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China.
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
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Porter KJ, Cao L, Chen Y, TerBush AD, Chen C, Erickson HP, Osteryoung KW. The Arabidopsis thaliana chloroplast division protein FtsZ1 counterbalances FtsZ2 filament stability in vitro. J Biol Chem 2021; 296:100627. [PMID: 33812992 PMCID: PMC8142252 DOI: 10.1016/j.jbc.2021.100627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/18/2022] Open
Abstract
Bacterial cell and chloroplast division are driven by a contractile “Z ring” composed of the tubulin-like cytoskeletal GTPase FtsZ. Unlike bacterial Z rings, which consist of a single FtsZ, the chloroplast Z ring in plants is composed of two FtsZ proteins, FtsZ1 and FtsZ2. Both are required for chloroplast division in vivo, but their biochemical relationship is poorly understood. We used GTPase assays, light scattering, transmission electron microscopy, and sedimentation assays to investigate the assembly behavior of purified Arabidopsis thaliana (At) FtsZ1 and AtFtsZ2 both individually and together. Both proteins exhibited GTPase activity. AtFtsZ2 assembled relatively quickly, forming protofilament bundles that were exceptionally stable, as indicated by their sustained assembly and slow disassembly. AtFtsZ1 did not form detectable protofilaments on its own. When mixed with AtFtsZ2, AtFtsZ1 reduced the extent and rate of AtFtsZ2 assembly, consistent with its previously demonstrated ability to promote protofilament subunit turnover in living cells. Mixing the two FtsZ proteins did not increase the overall GTPase activity, indicating that the effect of AtFtsZ1 on AtFtsZ2 assembly was not due to a stimulation of GTPase activity. However, the GTPase activity of AtFtsZ1 was required to reduce AtFtsZ2 assembly. Truncated forms of AtFtsZ1 and AtFtsZ2 consisting of only their conserved core regions largely recapitulated the behaviors of the full-length proteins. Our in vitro findings provide evidence that FtsZ1 counterbalances the stability of FtsZ2 filaments in the regulation of chloroplast Z-ring dynamics and suggest that restraining FtsZ2 self-assembly is a critical function of FtsZ1 in chloroplasts.
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Affiliation(s)
- Katie J Porter
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Lingyan Cao
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Yaodong Chen
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Allan D TerBush
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Cheng Chen
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Harold P Erickson
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
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4
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Abolhassani Rad S, Clayton EJ, Cornelius EJ, Howes TR, Kohalmi SE. Moonlighting proteins: putting the spotlight on enzymes. PLANT SIGNALING & BEHAVIOR 2018; 13:e1517075. [PMID: 30252596 PMCID: PMC6204816 DOI: 10.1080/15592324.2018.1517075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 06/11/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
AROGENATE DEHAYDRATASE2 (ADT2) is a member of the Arabidopsis thaliana ADT family. All members of this family act as arogenate dehydratases in phenylalanine biosynthesis, decarboxylating/dehydrating arogenate to phenylalanine. ADT2 is detected in stromules, and as a ring around the equatorial plane of dividing chloroplasts, indicating it has a second, non-enzymatic function in chloroplast division. Here, we provide further evidence for this alternative role of ADT2. First, we demonstrate that ADT2 and FtsZ co-localize around the equatorial plane at the same time. Second, FtsZ expression in an adt2 mutant was analyzed, as well as ADT2 expression in three Arabidopsis chloroplast division mutants, ACCUMULATION AND REPLICATION OF CHLOROPLASTS3 (ARC3), ARC5 and ARC6. In arc3 and arc6 mutants, ADT2 is misexpressed and resembles the expression of FtsZ in the same mutants. However, in the arc5 mutant, ADT2 ring positioning is observed at constriction points indicating proper relative timing. ADT2 expression in the arc mutants shows that the role of ADT2 in chloroplast division occurs prior to ARC5, but is dependent on ARC3 and ARC6. Abbreviations used: ADT: arogenate dehydratase, ARC: accumulation and replication of chloroplasts, CFP: cyan fluorescent protein, dpi: days post infiltration, FtsZ: filamentous temperature sensitive Z, PD: plastid division, Phe: phenylalanine, YFP: yellow fluorescent protein.
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Sung MW, Shaik R, TerBush AD, Osteryoung KW, Vitha S, Holzenburg A. The chloroplast division protein ARC6 acts to inhibit disassembly of GDP-bound FtsZ2. J Biol Chem 2018; 293:10692-10706. [PMID: 29769312 DOI: 10.1074/jbc.ra117.000999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/14/2018] [Indexed: 01/12/2023] Open
Abstract
Chloroplasts host photosynthesis and fulfill other metabolic functions that are essential to plant life. They have to divide by binary fission to maintain their numbers throughout cycles of cell division. Chloroplast division is achieved by a complex ring-shaped division machinery located on both the inner (stromal) and the outer (cytosolic) side of the chloroplast envelope. The inner division ring (termed the Z ring) is formed by the assembly of tubulin-like FtsZ1 and FtsZ2 proteins. ARC6 is a key chloroplast division protein that interacts with the Z ring. ARC6 spans the inner envelope membrane, is known to stabilize or maintain the Z ring, and anchors the Z ring to the inner membrane through interaction with FtsZ2. The underlying mechanism of Z ring stabilization is not well-understood. Here, biochemical and structural characterization of ARC6 was conducted using light scattering, sedimentation, and light and transmission EM. The recombinant protein was purified as a dimer. The results indicated that a truncated form of ARC6 (tARC6), representing the stromal portion of ARC6, affects FtsZ2 assembly without forming higher-order structures and exerts its effect via FtsZ2 dynamics. tARC6 prevented GDP-induced FtsZ2 disassembly and caused a significant net increase in FtsZ2 assembly when GDP was present. Single particle analysis and 3D reconstruction were performed to elucidate the structural basis of ARC6 activity. Together, the data reveal that a dimeric form of tARC6 binds to FtsZ2 filaments and does not increase FtsZ polymerization rates but rather inhibits GDP-associated FtsZ2 disassembly.
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Affiliation(s)
- Min Woo Sung
- From the Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Rahamthulla Shaik
- From the Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Allan D TerBush
- the Biochemistry and Molecular Biology Graduate Program and.,Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | | | - Stanislav Vitha
- the Microscopy and Imaging Center, Texas A&M University, College Station, Texas 77843, and
| | - Andreas Holzenburg
- From the Department of Biology, Texas A&M University, College Station, Texas 77843.,the Microscopy and Imaging Center, Texas A&M University, College Station, Texas 77843, and.,the Department of Biomedical Sciences, School of Medicine, University of Texas Rio Grande Valley, Brownsville-Edinburg-Harlingen, Texas 78550
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Irieda H, Shiomi D. Bacterial Heterologous Expression System for Reconstitution of Chloroplast Inner Division Ring and Evaluation of Its Contributors. Int J Mol Sci 2018; 19:ijms19020544. [PMID: 29439474 PMCID: PMC5855766 DOI: 10.3390/ijms19020544] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/23/2022] Open
Abstract
Plant chloroplasts originate from the symbiotic relationship between ancient free-living cyanobacteria and ancestral eukaryotic cells. Since the discovery of the bacterial derivative FtsZ gene—which encodes a tubulin homolog responsible for the formation of the chloroplast inner division ring (Z ring)—in the Arabidopsis genome in 1995, many components of the chloroplast division machinery were successively identified. The knowledge of these components continues to expand; however, the mode of action of the chloroplast dividing system remains unknown (compared to bacterial cell division), owing to the complexities faced in in planta analyses. To date, yeast and bacterial heterologous expression systems have been developed for the reconstitution of Z ring-like structures formed by chloroplast FtsZ. In this review, we especially focus on recent progress of our bacterial system using the model bacterium Escherichia coli to dissect and understand the chloroplast division machinery—an evolutionary hybrid structure composed of both bacterial (inner) and host-derived (outer) components.
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Affiliation(s)
- Hiroki Irieda
- Academic Assembly, Institute of Agriculture, Shinshu University, Nagano 399-4598, Japan.
| | - Daisuke Shiomi
- Department of Life Science, College of Science, Rikkyo University, Tokyo 171-8501, Japan.
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Chloroplast division protein ARC3 acts on FtsZ2 by preventing filament bundling and enhancing GTPase activity. Biochem J 2018; 475:99-115. [PMID: 29138260 DOI: 10.1042/bcj20170697] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 01/28/2023]
Abstract
Chloroplasts evolved from cyanobacterial endosymbiotic ancestors and their division is a complex process initiated by the assembly of cytoskeletal FtsZ (Filamentous temperature sensitive Z) proteins into a ring structure at the division site (Z-ring). The cyanobacterial Z-ring positioning system (MinCDE proteins) is also conserved in chloroplasts, except that MinC was lost and replaced by the eukaryotic ARC3 (accumulation and replication of chloroplasts). Both MinC and ARC3 act as negative regulators of FtsZ assembly, but ARC3 bears little sequence similarity with MinC. Here, light scattering assays, co-sedimentation, GTPase assay and transmission electron microscopy in conjunction with single-particle analysis have been used to elucidate the structure of ARC3 and its effect on its main target in chloroplast division, FtsZ2. Analysis of FtsZ2 in vitro assembly reactions in the presence and absence of GMPCPP showed that ARC3 promotes FtsZ2 debundling and disassembly of existing filaments in a concentration-dependent manner and requires GTP hydrolysis. Three-dimensional reconstruction of ARC3 revealed an almost circular molecule in which the FtsZ-binding N-terminus and the C-terminal PARC6 (paralog of ARC6)-binding MORN (Membrane Occupation and Recognition Nexus) domain are in close proximity and suggest a model for PARC6-enabled binding of ARC3 to FtsZ2. The latter is corroborated by in vivo data.
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8
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Fujiwara MT, Yasuzawa M, Sasaki S, Nakano T, Niwa Y, Yoshida S, Abe T, Itoh RD. The Arabidopsis minD mutation causes aberrant FtsZ1 ring placement and moderate heterogeneity of chloroplasts in the leaf epidermis. PLANT SIGNALING & BEHAVIOR 2017. [PMID: 28644708 PMCID: PMC5586359 DOI: 10.1080/15592324.2017.1343776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Symmetric division of leaf mesophyll chloroplasts requires MinD and MinE, which work together to suppress division other than at the mid-chloroplast. arc11 is a MinD loss-of-function mutant of Arabidopsis thaliana. In arc11 plants, asymmetric chloroplast division, as well as its delay or arrest, results in extreme size polymorphism of chloroplasts in mature mesophyll cells. The current study examined chloroplast phenotypes in the epidermis of arc11 leaves. Fluorescence microscopy analysis revealed that epidermal chloroplasts in mature leaves exhibited moderate heterogeneity in size. This probably resulted from completion of many of the previous non-equatorial or multiple division events in expanding leaves. Additionally, analyses of plastids found that epidermal chloroplasts in arc11 mutants showed several phenotypes that have not previously been described.
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Affiliation(s)
- Makoto T. Fujiwara
- Nishina Center and Plant Functions Laboratory, RIKEN, Wako, Saitama, Japan
- Department of Biology, Sophia University, Chiyoda, Tokyo, Japan
- CONTACT Makoto T. Fujiwara Department of Biology, Sophia University, 7–1 Kioicho, Chiyoda, Tokyo, 102-8554, Japan
| | - Mana Yasuzawa
- Department of Biology, Sophia University, Chiyoda, Tokyo, Japan
| | - Shun Sasaki
- Department of Biology, Sophia University, Chiyoda, Tokyo, Japan
| | - Takeshi Nakano
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama, Japan
- CREST, JST (Japan Science and Technology Agency), Kawaguchi, Saitama, Japan
| | - Yasuo Niwa
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Suruga, Shizuoka, Japan
| | - Shigeo Yoshida
- Nishina Center and Plant Functions Laboratory, RIKEN, Wako, Saitama, Japan
| | - Tomoko Abe
- Nishina Center and Plant Functions Laboratory, RIKEN, Wako, Saitama, Japan
| | - Ryuuichi D. Itoh
- Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, Japan
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ARC6-mediated Z ring-like structure formation of prokaryote-descended chloroplast FtsZ in Escherichia coli. Sci Rep 2017; 7:3492. [PMID: 28615720 PMCID: PMC5471200 DOI: 10.1038/s41598-017-03698-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/04/2017] [Indexed: 12/04/2022] Open
Abstract
Plant chloroplasts proliferate through binary fission, and the stromal-side molecules that are involved in chloroplast division are bacterial derivatives. As in bacteria, the prokaryotic tubulin homolog FtsZ assembles into a ring-like structure (Z ring) at mid-chloroplast, and this process is followed by constriction. However, the properties of chloroplast FtsZs remain unclarified. Here, we employed Escherichia coli as a novel heterologous system for expressing chloroplast FtsZs and their regulatory components. Fluorescently labelled Arabidopsis FtsZ2 efficiently assembled into long filaments in E. coli cells, and artificial membrane tethering conferred FtsZ2 filaments with the ability to form Z ring-like structures resembling the bacterial Z ring. A negative regulator of chloroplast FtsZ assembly, ARC3, retained its inhibitory effects on FtsZ2 filamentation and Z ring-like structure formation in E. coli cells. Thus, we provide a novel heterologous system by using bacterial cells to study the regulation of the chloroplast divisome. Furthermore, we demonstrated that the FtsZ2-interacting protein ARC6, which is a potential candidate for Z ring tethering to the chloroplast inner envelope membrane, genuinely targeted FtsZ2 to the membrane components and supported its morphological shift from linear filaments to Z ring-like structures in a manner dependent on the C-terminal ARC6-interacting domain of FtsZ2.
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MacCready JS, Schossau J, Osteryoung KW, Ducat DC. Robust Min-system oscillation in the presence of internal photosynthetic membranes in cyanobacteria. Mol Microbiol 2016; 103:483-503. [PMID: 27891682 DOI: 10.1111/mmi.13571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2016] [Indexed: 11/29/2022]
Abstract
The oscillatory Min system of Escherichia coli defines the cell division plane by regulating the site of FtsZ-ring formation and represents one of the best-understood examples of emergent protein self-organization in nature. The oscillatory patterns of the Min-system proteins MinC, MinD and MinE (MinCDE) are strongly dependent on the geometry of membranes they bind. Complex internal membranes within cyanobacteria could disrupt this self-organization by sterically occluding or sequestering MinCDE from the plasma membrane. Here, it was shown that the Min system in the cyanobacterium Synechococcus elongatus PCC 7942 oscillates from pole-to-pole despite the potential spatial constraints imposed by their extensive thylakoid network. Moreover, reaction-diffusion simulations predict robust oscillations in modeled cyanobacterial cells provided that thylakoid network permeability is maintained to facilitate diffusion, and suggest that Min proteins require preferential affinity for the plasma membrane over thylakoids to correctly position the FtsZ ring. Interestingly, in addition to oscillating, MinC exhibits a midcell localization dependent on MinD and the DivIVA-like protein Cdv3, indicating that two distinct pools of MinC are coordinated in S. elongatus. Our results provide the first direct evidence for Min oscillation outside of E. coli and have broader implications for Min-system function in bacteria and organelles with internal membrane systems.
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Affiliation(s)
- Joshua S MacCready
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Jory Schossau
- Department of Computer Science, Michigan State University, East Lansing, MI, 48824, USA
| | | | - Daniel C Ducat
- Department of Biochemistry, MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
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TerBush AD, Porzondek CA, Osteryoung KW. Functional Analysis of the Chloroplast Division Complex Using Schizosaccharomyces pombe as a Heterologous Expression System. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:275-289. [PMID: 26917361 DOI: 10.1017/s1431927616000143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chloroplast division is driven by a macromolecular complex that assembles at the midplastid. The FtsZ ring (Z ring) is the central structure in this complex, and is composed of the functionally distinct cytoskeletal proteins FtsZ1 and FtsZ2. Recent studies in the heterologous Schizosaccharomyces pombe system showed that Arabidopsis FtsZ1 and FtsZ2 filaments have distinct assembly and turnover characteristics. To further analyze these FtsZs, we employed this system to compare the assembly and dynamic properties of FtsZ1 and FtsZ2 lacking their N- and/or C-termini with those of their full-length counterparts. Our data provide evidence that the N-terminus of FtsZ2 is critical for its structural dominance over FtsZ1, and that the N- and C-termini promote polymer bundling and turnover of both FtsZs and contribute to their distinct behaviors. We also assessed how ARC6 affects FtsZ2 filament dynamics, and found that it interacts with and stabilizes FtsZ2 filaments in S. pombe independent of its presumed Z-ring tethering function in planta. Finally, we generated FtsZ1-FtsZ2 coexpression constructs to facilitate reconstitution of more complex interaction networks. Our experiments yield new insight into factors influencing FtsZ behavior and highlight the utility of S. pombe for analyzing chloroplast FtsZs and their assembly regulators.
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Affiliation(s)
- Allan D TerBush
- 1Biochemistry and Molecular Biology Graduate Program,Michigan State University,East Lansing,MI 48824,USA
| | - Chris A Porzondek
- 3Biochemistry and Molecular Biology Undergraduate Program,Michigan State University,East Lansing,MI 48824,USA
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