The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus

The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus PDF Author: Natalie Anne Dye
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 286

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Book Description
This work focuses on the mechanism by which MreB contributes to the maintenance of cell shape in the gram-negative alpha-proteobacterium Caulobacter crescentus. The gene mreB encodes a protein that resembles actin, a eukaryotic cytoskeletal protein. Previously, it was shown that mreB is required to maintain a rod-like shape and localizes to a helical pattern near the cytoplasmic membrane. Here, we show that MreB is associated with regions of active growth in Caulobacter, as mutant strains that mislocalize MreB to the cell poles direct new growth at or near the poles. We present evidence to suggest that MreB contributes to the determination of proper length, width, and curvature through partially distinct mechanisms. The determination of proper width involves the essential proteins MreC and Pbp2, which are encoded in the mreB operon. While MreB and MreC are both required to position the cell wall transpeptidase Pbp2 along the lateral sidewalls and away from midcell, the two do not colocalize and each can maintain its localization in the absence of the other. When MreB is mislocalized to the poles, MreC and Pbp2 do not follow. These data argue against the idea that MreB provides a scaffold-like structure to localize enzymes that directly modify the cell wall. The determination of proper curvature, involves the intermediate filament-like protein, Crescentin. We identify a putative binding site on MreB for Crescentin or other curvature-mediating factors. We also show that the extent to which the subcellular localization of MreB changes over the cell cycle is correlated with cell size, indicating that MreB is involved in the coordination between elongation and division. In addition, we show that in vitro purified MreB spontaneously forms very stable polymers in the presence or absence of nucleotide. These polymers are globular or amorphous and only filamentous when placed on a highly positively charged surface of Poly-L-lysine. These in vitro data suggest that MreB is likely to be regulated at the disassembly step in the cell and that the cellular environment may influence the structure of MreB polymers. Lastly, we present biochemical evidence to support the existence of a disassembly factor in cytoplasmic Caulobacter extract. Together our data suggest that the maintenance of the crescent-rod cell shape in Caulobacter is the result of a complicated balance between MreB's dynamic subcellular localization, polymeric structure, and communication with cellular components.

The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus

The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus PDF Author: Natalie Anne Dye
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 286

Get Book Here

Book Description
This work focuses on the mechanism by which MreB contributes to the maintenance of cell shape in the gram-negative alpha-proteobacterium Caulobacter crescentus. The gene mreB encodes a protein that resembles actin, a eukaryotic cytoskeletal protein. Previously, it was shown that mreB is required to maintain a rod-like shape and localizes to a helical pattern near the cytoplasmic membrane. Here, we show that MreB is associated with regions of active growth in Caulobacter, as mutant strains that mislocalize MreB to the cell poles direct new growth at or near the poles. We present evidence to suggest that MreB contributes to the determination of proper length, width, and curvature through partially distinct mechanisms. The determination of proper width involves the essential proteins MreC and Pbp2, which are encoded in the mreB operon. While MreB and MreC are both required to position the cell wall transpeptidase Pbp2 along the lateral sidewalls and away from midcell, the two do not colocalize and each can maintain its localization in the absence of the other. When MreB is mislocalized to the poles, MreC and Pbp2 do not follow. These data argue against the idea that MreB provides a scaffold-like structure to localize enzymes that directly modify the cell wall. The determination of proper curvature, involves the intermediate filament-like protein, Crescentin. We identify a putative binding site on MreB for Crescentin or other curvature-mediating factors. We also show that the extent to which the subcellular localization of MreB changes over the cell cycle is correlated with cell size, indicating that MreB is involved in the coordination between elongation and division. In addition, we show that in vitro purified MreB spontaneously forms very stable polymers in the presence or absence of nucleotide. These polymers are globular or amorphous and only filamentous when placed on a highly positively charged surface of Poly-L-lysine. These in vitro data suggest that MreB is likely to be regulated at the disassembly step in the cell and that the cellular environment may influence the structure of MreB polymers. Lastly, we present biochemical evidence to support the existence of a disassembly factor in cytoplasmic Caulobacter extract. Together our data suggest that the maintenance of the crescent-rod cell shape in Caulobacter is the result of a complicated balance between MreB's dynamic subcellular localization, polymeric structure, and communication with cellular components.

The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus

The Assembly and Interactions of MreB in the Maintenance of Cell Shape in Caulobacter Crescentus PDF Author: Natalie Anne Dye
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
This work focuses on the mechanism by which MreB contributes to the maintenance of cell shape in the gram-negative alpha-proteobacterium Caulobacter crescentus. The gene mreB encodes a protein that resembles actin, a eukaryotic cytoskeletal protein. Previously, it was shown that mreB is required to maintain a rod-like shape and localizes to a helical pattern near the cytoplasmic membrane. Here, we show that MreB is associated with regions of active growth in Caulobacter, as mutant strains that mislocalize MreB to the cell poles direct new growth at or near the poles. We present evidence to suggest that MreB contributes to the determination of proper length, width, and curvature through partially distinct mechanisms. The determination of proper width involves the essential proteins MreC and Pbp2, which are encoded in the mreB operon. While MreB and MreC are both required to position the cell wall transpeptidase Pbp2 along the lateral sidewalls and away from midcell, the two do not colocalize and each can maintain its localization in the absence of the other. When MreB is mislocalized to the poles, MreC and Pbp2 do not follow. These data argue against the idea that MreB provides a scaffold-like structure to localize enzymes that directly modify the cell wall. The determination of proper curvature, involves the intermediate filament-like protein, Crescentin. We identify a putative binding site on MreB for Crescentin or other curvature-mediating factors. We also show that the extent to which the subcellular localization of MreB changes over the cell cycle is correlated with cell size, indicating that MreB is involved in the coordination between elongation and division. In addition, we show that in vitro purified MreB spontaneously forms very stable polymers in the presence or absence of nucleotide. These polymers are globular or amorphous and only filamentous when placed on a highly positively charged surface of Poly-L-lysine. These in vitro data suggest that MreB is likely to be regulated at the disassembly step in the cell and that the cellular environment may influence the structure of MreB polymers. Lastly, we present biochemical evidence to support the existence of a disassembly factor in cytoplasmic Caulobacter extract. Together our data suggest that the maintenance of the crescent-rod cell shape in Caulobacter is the result of a complicated balance between MreB's dynamic subcellular localization, polymeric structure, and communication with cellular components.

Prokaryotic Cytoskeletons

Prokaryotic Cytoskeletons PDF Author: Jan Löwe
Publisher: Springer
ISBN: 331953047X
Category : Science
Languages : en
Pages : 457

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Book Description
This book describes the structures and functions of active protein filaments, found in bacteria and archaea, and now known to perform crucial roles in cell division and intra-cellular motility, as well as being essential for controlling cell shape and growth. These roles are possible because the cytoskeletal and cytomotive filaments provide long range order from small subunits. Studies of these filaments are therefore of central importance to understanding prokaryotic cell biology. The wide variation in subunit and polymer structure and its relationship with the range of functions also provide important insights into cell evolution, including the emergence of eukaryotic cells. Individual chapters, written by leading researchers, review the great advances made in the past 20-25 years, and still ongoing, to discover the architectures, dynamics and roles of filaments found in relevant model organisms. Others describe one of the families of dynamic filaments found in many species. The most common types of filament are deeply related to eukaryotic cytoskeletal proteins, notably actin and tubulin that polymerise and depolymerise under the control of nucleotide hydrolysis. Related systems are found to perform a variety of roles, depending on the organisms. Surprisingly, prokaryotes all lack the molecular motors associated with eukaryotic F-actin and microtubules. Archaea, but not bacteria, also have active filaments related to the eukaryotic ESCRT system. Non-dynamic fibres, including intermediate filament-like structures, are known to occur in some bacteria.. Details of known filament structures are discussed and related to what has been established about their molecular mechanisms, including current controversies. The final chapter covers the use of some of these dynamic filaments in Systems Biology research. The level of information in all chapters is suitable both for active researchers and for advanced students in courses involving bacterial or archaeal physiology, molecular microbiology, structural cell biology, molecular motility or evolution. Chapter 3 of this book is open access under a CC BY 4.0 license.

Control of Morphogenesis in Caulobacter Crescentus

Control of Morphogenesis in Caulobacter Crescentus PDF Author: Arun Venkat Divakaruni
Publisher:
ISBN:
Category :
Languages : en
Pages : 374

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Book Description


Comprehensive Biophysics

Comprehensive Biophysics PDF Author:
Publisher: Academic Press
ISBN: 0080957188
Category : Science
Languages : en
Pages : 3533

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Book Description
Biophysics is a rapidly-evolving interdisciplinary science that applies theories and methods of the physical sciences to questions of biology. Biophysics encompasses many disciplines, including physics, chemistry, mathematics, biology, biochemistry, medicine, pharmacology, physiology, and neuroscience, and it is essential that scientists working in these varied fields are able to understand each other's research. Comprehensive Biophysics, Nine Volume Set will help bridge that communication gap. Written by a team of researchers at the forefront of their respective fields, under the guidance of Chief Editor Edward Egelman, Comprehensive Biophysics, Nine Volume Set provides definitive introductions to a broad array of topics, uniting different areas of biophysics research - from the physical techniques for studying macromolecular structure to protein folding, muscle and molecular motors, cell biophysics, bioenergetics and more. The result is this comprehensive scientific resource - a valuable tool both for helping researchers come to grips quickly with material from related biophysics fields outside their areas of expertise, and for reinforcing their existing knowledge. Biophysical research today encompasses many areas of biology. These studies do not necessarily share a unique identifying factor. This work unites the different areas of research and allows users, regardless of their background, to navigate through the most essential concepts with ease, saving them time and vastly improving their understanding The field of biophysics counts several journals that are directly and indirectly concerned with the field. There is no reference work that encompasses the entire field and unites the different areas of research through deep foundational reviews. Comprehensive Biophysics fills this vacuum, being a definitive work on biophysics. It will help users apply context to the diverse journal literature offering, and aid them in identifying areas for further research Chief Editor Edward Egelman (E-I-C, Biophysical Journal) has assembled an impressive, world-class team of Volume Editors and Contributing Authors. Each chapter has been painstakingly reviewed and checked for consistent high quality. The result is an authoritative overview which ties the literature together and provides the user with a reliable background information and citation resource

Assembly Properties of the Bacillus Subtilis Actin Orthologues MreB, MreBH, and Mbl

Assembly Properties of the Bacillus Subtilis Actin Orthologues MreB, MreBH, and Mbl PDF Author: Joshua Alan Mayer
Publisher:
ISBN:
Category :
Languages : en
Pages : 232

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Book Description


Bacterial Physiology

Bacterial Physiology PDF Author: Walid El-Sharoud
Publisher: Springer Science & Business Media
ISBN: 3540749217
Category : Science
Languages : en
Pages : 377

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Book Description
The application of new molecular methodologies in the study of bacterial behavior and cell architecture has enabled new revolutionary insights and discoveries in these areas. This new text presents recent developments in bacterial physiology that are highly relevant to a wide range of readership including those interested in basic and applied knowledge. Its chapters are written by international scientific authorities at the forefront of the subject. The value of this recent knowledge in bacterial physiology is not only restricted to fundamental biology. It also extends to biotechnology and drug-discovery disciplines.

Asymmetric Cell Division in Development, Differentiation and Cancer

Asymmetric Cell Division in Development, Differentiation and Cancer PDF Author: Jean-Pierre Tassan
Publisher: Springer
ISBN: 3319531506
Category : Science
Languages : en
Pages : 421

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Book Description
This book provides readers with an overview of the frequent occurrence of asymmetric cell division. Employing a broad range of examples, it highlights how this mode of cell division constitutes the basis of multicellular organism development and how its misregulation can lead to cancer. To underline such developmental correlations, readers will for example gain insights into stem cell fate and tumor growth. In turn, subsequent chapters include descriptions of asymmetric cell division from unicellular organisms to humans in both physiological and pathological conditions. The book also illustrates the importance of this process for evolution and our need to understand the background mechanisms, offering a valuable guide not only for students in the field of developmental biology but also for experienced researchers from neighboring fields.

Prokaryotic Metabolism and Physiology

Prokaryotic Metabolism and Physiology PDF Author: Byung Hong Kim
Publisher: Cambridge University Press
ISBN: 1107171733
Category : Medical
Languages : en
Pages : 509

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Book Description
Extensive and up-to-date review of key metabolic processes in bacteria and archaea and how metabolism is regulated under various conditions.

Sequence — Evolution — Function

Sequence — Evolution — Function PDF Author: Eugene V. Koonin
Publisher: Springer Science & Business Media
ISBN: 1475737831
Category : Science
Languages : en
Pages : 482

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Book Description
Sequence - Evolution - Function is an introduction to the computational approaches that play a critical role in the emerging new branch of biology known as functional genomics. The book provides the reader with an understanding of the principles and approaches of functional genomics and of the potential and limitations of computational and experimental approaches to genome analysis. Sequence - Evolution - Function should help bridge the "digital divide" between biologists and computer scientists, allowing biologists to better grasp the peculiarities of the emerging field of Genome Biology and to learn how to benefit from the enormous amount of sequence data available in the public databases. The book is non-technical with respect to the computer methods for genome analysis and discusses these methods from the user's viewpoint, without addressing mathematical and algorithmic details. Prior practical familiarity with the basic methods for sequence analysis is a major advantage, but a reader without such experience will be able to use the book as an introduction to these methods. This book is perfect for introductory level courses in computational methods for comparative and functional genomics.