The extended tubulin superfamily

2001 ◽  
Vol 114 (15) ◽  
pp. 2723-2733 ◽  
Author(s):  
Paul G. McKean ◽  
Sue Vaughan ◽  
Keith Gull
Keyword(s):  
Cell Biology ◽  
Structure And Function ◽  
Microtubule Assembly ◽  
Eukaryotic Cells ◽  
Current Evidence ◽  
Post Translational Modification ◽  
Tubulin Isotypes ◽  
The Past ◽  
And Function

Although most eukaryotic cells can express multiple isotypes of αβ-tubulin, the significance of this diversity has not always been apparent. Recent data indicate that particular αβ-tubulin isotypes, both genome encoded and those derived by post-translational modification, can directly influence microtubule structure and function — thus validating ideas originally proposed in the multitubulin hypothesis over 25 years ago.It has also become increasingly evident over the past year that some (but intriguingly not all) eukaryotes encode several other tubulin proteins, and to date five further members of the tubulin superfamily, γ, δ, ϵ, 𝛇 and η, have been identified. Although the role of γ-tubulin in the nucleation of microtubule assembly is now well established, far less is known about the functions of δ-, ϵ-, 𝛇- and η-tubulin. Recent work has expanded our knowledge of the functions and localisation of these newer members of the tubulin superfamily, and the emerging data suggesting a restricted evolutionary distribution of these `new' tubulin proteins, conforms to established knowledge of microtubule cell biology. On the basis of current evidence, we predict that δ-, ϵ-, 𝛇- and η-tubulin all have functions associated with the centriole or basal body of eukaryotic cells and organisms.

scholarly journals Class V β-tubulin alters dynamic instability and stimulates microtubule detachment from centrosomes

2011 ◽  
Vol 22 (7) ◽  
pp. 1025-1034 ◽  
Author(s):  
Rajat Bhattacharya ◽  
Hailing Yang ◽  
Fernando Cabral
Keyword(s):  
Cell Division ◽  
Dynamic Instability ◽  
Microtubule Assembly ◽  
Class V ◽  
Tubulin Isotypes ◽  
Specific Manner ◽  
Microtubule Growth ◽  
A Minor ◽  
And Function

A multigene family produces tubulin isotypes that are expressed in a tissue-specific manner, but the role of these isotypes in microtubule assembly and function is unclear. Recently we showed that overexpression or depletion of β5-tubulin, a minor isotype with wide tissue distribution, inhibits cell division. We now report that elevated β5-tubulin causes uninterrupted episodes of microtubule shortening and increased shortening rates. Conversely, depletion of β5-tubulin reduces shortening rates and causes very short excursions of growth and shortening. A tubulin conformation-sensitive antibody indicated that the uninterrupted shortening can be explained by a relative absence of stabilized patches along the microtubules that contain tubulin in an assembly-competent conformation and normally act to restore microtubule growth. In addition to these changes in dynamic instability, overexpression of β5-tubulin causes fragmentation that results from microtubule detachment from centrosomes, and it is this activity that best explains the effects of β5 on cell division. Paclitaxel inhibits microtubule detachment, increases the number of assembly-competent tubulin patches, and inhibits microtubule shortening, thus providing an explanation for why the drug can counteract the phenotypic effects of β5 overexpression. On the basis of these observations, we propose that cells can use β5-tubulin expression to adjust the behavior of the microtubule cytoskeleton.

Progress in ultrastructural and molecular analysis of the nuclear matrix

1992 ◽  
Vol 50 (1) ◽  
pp. 508-509
Author(s):  
Edward G. Fey
Keyword(s):  
Electron Microscopy ◽  
Nuclear Matrix ◽  
Structure And Function ◽  
Matrix Proteins ◽  
Rna Transcription ◽  
Nuclear Matrix Proteins ◽  
The Past ◽  
And Function

In the past few years, considerable advances have been made regarding the structure and function of the nuclear matrix. In the first half of this presentation, the field of nuclear matrix research will be summarized. Emphasis will be placed on those studies where molecular interactions are demonstrated in situ utilizing high resolution light and/or electron microscopy. Studies demonstrating the role of the nuclear matrix in DNA synthesis and replication, RNA transcription and processing, and the binding of matrix attachment regions to specific nuclear matrix proteins will be summarized.

Structure and function: organization of a medical specialty for the rest of the 20th century

1982 ◽  
Vol 57 (3) ◽  
pp. 301-308 ◽  
Author(s):  
W. Kemp Clark
Keyword(s):  
20Th Century ◽  
American Association ◽  
Medical Specialty ◽  
Structure And Function ◽  
Concerted Effort ◽  
Content Type ◽  
The Past ◽  
And Function ◽  
Fine Print

✓ The President of the American Association of Neurological Surgeons concentrates on the problems facing the specialty, the achievements of the past, and the mechanisms designed to foster the advancement and role of neurosurgery. To counter the difficult days ahead, he emphasizes the need for concerted effort and action on the part of neurosurgeons within the umbrella of the Association as spokesman for the specialty and advocate for the patients' welfare.

scholarly journals DNA Polymerases at the Eukaryotic Replication Fork Thirty Years after: Connection to Cancer

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3489
Author(s):  
Youri I. Pavlov ◽  
Anna S. Zhuk ◽  
Elena I. Stepchenkova
Keyword(s):  
Replication Fork ◽  
Genome Instability ◽  
Dna Polymerases ◽  
Structure And Function ◽  
The Past ◽  
New Findings ◽  
Dna Strands ◽  
Leading Strand ◽  
And Function

Recent studies on tumor genomes revealed that mutations in genes of replicative DNA polymerases cause a predisposition for cancer by increasing genome instability. The past 10 years have uncovered exciting details about the structure and function of replicative DNA polymerases and the replication fork organization. The principal idea of participation of different polymerases in specific transactions at the fork proposed by Morrison and coauthors 30 years ago and later named “division of labor,” remains standing, with an amendment of the broader role of polymerase δ in the replication of both the lagging and leading DNA strands. However, cancer-associated mutations predominantly affect the catalytic subunit of polymerase ε that participates in leading strand DNA synthesis. We analyze how new findings in the DNA replication field help elucidate the polymerase variants’ effects on cancer.

scholarly journals Intestinal Barrier Function in Health and Disease—Any Role of SARS-CoV-2?

2020 ◽  
Vol 8 (11) ◽  
pp. 1744
Author(s):  
Lakshya Sharma ◽  
Antonio Riva
Keyword(s):  
Intestinal Barrier ◽  
Therapeutic Strategies ◽  
Structure And Function ◽  
Intestinal Barrier Function ◽  
Current Evidence ◽  
Barrier Functions ◽  
Microbial Dysbiosis ◽  
Health And Disease ◽  
And Function

Alterations in the structure and function of the intestinal barrier play a role in the pathogenesis of a multitude of diseases. During the recent and ongoing coronavirus disease (COVID-19) pandemic, it has become clear that the gastrointestinal system and the gut barrier may be affected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, and disruption of barrier functions or intestinal microbial dysbiosis may have an impact on the progression and severity of this new disease. In this review, we aim to provide an overview of current evidence on the involvement of gut alterations in human disease including COVID-19, with a prospective outlook on supportive therapeutic strategies that may be investigated to rescue intestinal barrier functions and possibly facilitate clinical improvement in these patients.

scholarly journals Mitochondrial Kinases and the Role of Mitochondrial Protein Phosphorylation in Health and Disease

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 82
Author(s):  
Veronika Kotrasová ◽  
Barbora Keresztesová ◽  
Gabriela Ondrovičová ◽  
Jacob A. Bauer ◽  
Henrieta Havalová ◽  
...  
Keyword(s):  
Mitochondrial Biogenesis ◽  
Mitochondrial Protein ◽  
Structure And Function ◽  
Stress Factors ◽  
Mitochondrial Proteins ◽  
Post Translational Modification ◽  
Mitochondrial Structure ◽  
Health And Disease ◽  
And Function

The major role of mitochondria is to provide cells with energy, but no less important are their roles in responding to various stress factors and the metabolic changes and pathological processes that might occur inside and outside the cells. The post-translational modification of proteins is a fast and efficient way for cells to adapt to ever changing conditions. Phosphorylation is a post-translational modification that signals these changes and propagates these signals throughout the whole cell, but it also changes the structure, function and interaction of individual proteins. In this review, we summarize the influence of kinases, the proteins responsible for phosphorylation, on mitochondrial biogenesis under various cellular conditions. We focus on their role in keeping mitochondria fully functional in healthy cells and also on the changes in mitochondrial structure and function that occur in pathological processes arising from the phosphorylation of mitochondrial proteins.

From protoplasmic theory to cellular systems biology: a 150-year reflection

2010 ◽  
Vol 298 (6) ◽  
pp. C1280-C1290 ◽  
Author(s):  
G. Rickey Welch ◽  
James S. Clegg
Keyword(s):  
Systems Biology ◽  
Cell Biology ◽  
Cell Structure ◽  
Structure And Function ◽  
Cellular Systems ◽  
Controversial Issues ◽  
Cell Theory ◽  
History Of ◽  
And Function

Present-day cellular systems biology is producing data on an unprecedented scale. This field has generated a renewed interest in the holistic, “system” character of cell structure-and-function. Underlying the data deluge, however, there is a clear and present need for a historical foundation. The origin of the “system” view of the cell dates to the birth of the protoplasm concept. The 150-year history of the role of “protoplasm” in cell biology is traced. It is found that the “protoplasmic theory,” not the “cell theory,” was the key 19th-century construct that drove the study of the structure-and-function of living cells and set the course for the development of modern cell biology. The evolution of the “protoplasm” picture into the 20th century is examined by looking at controversial issues along the way and culminating in the current views on the role of cytological organization in cellular activities. The relevance of the “protoplasmic theory” to 21st-century cellular systems biology is considered.

scholarly journals Stiffness Sensing by Cells

2020 ◽  
Vol 100 (2) ◽  
pp. 695-724 ◽  
Author(s):  
Paul A. Janmey ◽  
Daniel A. Fletcher ◽  
Cynthia A. Reinhart-King
Keyword(s):  
Cell Biology ◽  
Cell Structure ◽  
Structure And Function ◽  
Substrate Stiffness ◽  
Common Features ◽  
The Past ◽  
Simple Rules ◽  
Physical Stimuli ◽  
Disease Initiation ◽  
And Function

Physical stimuli are essential for the function of eukaryotic cells, and changes in physical signals are important elements in normal tissue development as well as in disease initiation and progression. The complexity of physical stimuli and the cellular signals they initiate are as complex as those triggered by chemical signals. One of the most important, and the focus of this review, is the effect of substrate mechanical properties on cell structure and function. The past decade has produced a nearly exponentially increasing number of mechanobiological studies to define how substrate stiffness alters cell biology using both purified systems and intact tissues. Here we attempt to identify common features of mechanosensing in different systems while also highlighting the numerous informative exceptions to what in early studies appeared to be simple rules by which cells respond to mechanical stresses.

scholarly journals Mitochondria in Health and Diseases

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1177 ◽  
Author(s):  
Sabzali Javadov ◽  
Andrey V. Kozlov ◽  
Amadou K. S. Camara
Keyword(s):  
Cell Death ◽  
Animal Models ◽  
Human Diseases ◽  
Eukaryotic Cells ◽  
Special Issue ◽  
Subcellular Organelles ◽  
The Past ◽  
Cell Life ◽  
And Function

Mitochondria are subcellular organelles evolved by endosymbiosis of bacteria with eukaryotic cells characteristics. They are the main source of ATP in the cell and play a pivotal role in cell life and cell death. Mitochondria are engaged in the pathogenesis of human diseases and aging directly or indirectly through a broad range of signaling pathways. However, despite an increased interest in mitochondria over the past decades, the mechanisms of mitochondria-mediated cell/organ dysfunction in response to pathological stimuli remain unknown. The Special Issue, “Mitochondria in Health and Diseases,” organized by Cells includes 24 review and original articles that highlight the latest achievements in elucidating the role of mitochondria under physiological (healthy) conditions and, in various cell/animal models of human diseases and, in patients. Altogether, the Special Issue summarizes and discusses different aspects of mitochondrial metabolism and function that open new avenues in understanding mitochondrial biology.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

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