MOLECULAR REGULATORY MECHANISMS OF NYCTOHEMERAL RHYTHMS IN HEPATIC CELL DIVISION AND FUNCTION

1980 ◽  
pp. 345-362 ◽  
Author(s):  
H. Barbason ◽  
F. De Parmentier ◽  
J. Van Cantfort
Keyword(s):  
Cell Division ◽  
Hepatic Cell ◽  
Regulatory Mechanisms ◽  
And Function ◽  
Molecular Regulatory Mechanisms

scholarly journals Brain Long Noncoding RNAs: Multitask Regulators of Neuronal Differentiation and Function

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3951
Author(s):  
Sarva Keihani ◽  
Verena Kluever ◽  
Eugenio F. Fornasiero
Keyword(s):  
Neuronal Differentiation ◽  
Neuronal Excitability ◽  
Noncoding Rnas ◽  
Long Noncoding Rnas ◽  
Regulatory Mechanisms ◽  
Control Robustness ◽  
Living Organisms ◽  
And Function ◽  
Regulatory Functions ◽  
Neuronal Physiology

The extraordinary cellular diversity and the complex connections established within different cells types render the nervous system of vertebrates one of the most sophisticated tissues found in living organisms. Such complexity is ensured by numerous regulatory mechanisms that provide tight spatiotemporal control, robustness and reliability. While the unusual abundance of long noncoding RNAs (lncRNAs) in nervous tissues was traditionally puzzling, it is becoming clear that these molecules have genuine regulatory functions in the brain and they are essential for neuronal physiology. The canonical view of RNA as predominantly a ‘coding molecule’ has been largely surpassed, together with the conception that lncRNAs only represent ‘waste material’ produced by cells as a side effect of pervasive transcription. Here we review a growing body of evidence showing that lncRNAs play key roles in several regulatory mechanisms of neurons and other brain cells. In particular, neuronal lncRNAs are crucial for orchestrating neurogenesis, for tuning neuronal differentiation and for the exact calibration of neuronal excitability. Moreover, their diversity and the association to neurodegenerative diseases render them particularly interesting as putative biomarkers for brain disease. Overall, we foresee that in the future a more systematic scrutiny of lncRNA functions will be instrumental for an exhaustive understanding of neuronal pathophysiology.

scholarly journals Midbody: From the Regulator of Cytokinesis to Postmitotic Signaling Organelle

Medicina ◽  
2018 ◽  
Vol 54 (4) ◽  
pp. 53 ◽  
Author(s):  
Ieva Antanavičiūtė ◽  
Paulius Gibieža ◽  
Rytis Prekeris ◽  
Vytenis Skeberdis
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Intercellular Bridge ◽  
Large Protein ◽  
Daughter Cells ◽  
First Case ◽  
Tumorigenic Potential ◽  
The One ◽  
And Function ◽  
Protein Rich

Faithful cell division is crucial for successful proliferation, differentiation, and development of cells, tissue homeostasis, and preservation of genomic integrity. Cytokinesis is a terminal stage of cell division, leaving two genetically identical daughter cells connected by an intercellular bridge (ICB) containing the midbody (MB), a large protein-rich organelle, in the middle. Cell division may result in asymmetric or symmetric abscission of the ICB. In the first case, the ICB is severed on the one side of the MB, and the MB is inherited by the opposite daughter cell. In the second case, the MB is cut from both sides, expelled into the extracellular space, and later it can be engulfed by surrounding cells. Cells with lower autophagic activity, such as stem cells and cancer stem cells, are inclined to accumulate MBs. Inherited MBs affect cell polarity, modulate intra- and intercellular communication, enhance pluripotency of stem cells, and increase tumorigenic potential of cancer cells. In this review, we briefly summarize the latest knowledge on MB formation, inheritance, degradation, and function, and in addition, present and discuss our recent findings on the electrical and chemical communication of cells connected through the MB-containing ICB.

scholarly journals The mitotic spindle protein CKAP2 potently increases formation and stability of microtubules

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Thomas S McAlear ◽  
Susanne Bechstedt
Keyword(s):  
Cell Division ◽  
Growth Factor ◽  
Mitotic Spindle ◽  
Apparent Rate Constant ◽  
Microtubule Dynamics ◽  
Proliferation Marker ◽  
Microtubule Growth ◽  
Large Rearrangements ◽  
And Function

Cells increase microtubule dynamics to make large rearrangements to their microtubule cytoskeleton during cell division. Changes in microtubule dynamics are essential for the formation and function of the mitotic spindle, and misregulation can lead to aneuploidy and cancer. Using in vitro reconstitution assays we show that the mitotic spindle protein Cytoskeleton-Associated Protein 2 (CKAP2) has a strong effect on nucleation of microtubules by lowering the critical tubulin concentration 100-fold. CKAP2 increases the apparent rate constant ka of microtubule growth by 50-fold and increases microtubule growth rates. In addition, CKAP2 strongly suppresses catastrophes. Our results identify CKAP2 as the most potent microtubule growth factor to date. These finding help explain CKAP2's role as an important spindle protein, proliferation marker, and oncogene.

scholarly journals Separase cleaves the kinetochore protein Meikin to direct the meiosis I/II transition

2020 ◽  
Author(s):  
Nolan K Maier ◽  
Jun Ma ◽  
Michael A Lampson ◽  
Iain M Cheeseman
Keyword(s):  
Cell Division ◽  
Germ Cells ◽  
Molecular Switch ◽  
Specific Protein ◽  
Cleavage Product ◽  
Regulatory Mechanisms ◽  
Kinetochore Protein ◽  
Chromosome Alignment ◽  
Activity State ◽  
Meiosis I

SummaryTo generate haploid gametes, germ cells undergo two consecutive meiotic divisions requiring key changes to the cell division machinery. Here, we explore the regulatory mechanisms that differentially control meiotic events. We demonstrate that the protease Separase rewires key cell division processes at the meiosis I/II transition by cleaving the meiosis-specific protein Meikin. In contrast to cohesin, which is inactivated by Separase proteolysis, cleaved Meikin remains functional, but results in a distinct activity state. Full-length Meikin and the C-terminal Meikin Separase-cleavage product both localize to kinetochores, bind to Plk1 kinase, and promote Rec8 cleavage, but our results reveal distinct roles for these proteins in controlling meiosis. Mutations that prevent Meikin cleavage or that conditionally inactivate Meikin at anaphase I both result in defective meiosis II chromosome alignment. Thus, Separase cleavage of Meikin creates an irreversible molecular switch to rewire the cell division machinery at the meiosis I/II transition.

Genetic rescue of muscle defects associated with a mutant Drosophila melanogaster tropomyosin allele

1987 ◽  
Vol 7 (8) ◽  
pp. 2977-2980
Author(s):  
E A Fyrberg ◽  
C C Karlik
Keyword(s):  
Germ Line ◽  
Regulatory Mechanisms ◽  
Directed Mutagenesis ◽  
Transformation System ◽  
Wild Type ◽  
Genetic Rescue ◽  
Transformation Protocol ◽  
Type Gene ◽  
Genetic Transformation System ◽  
And Function

We describe a genetic transformation system which should prove useful for investigating tropomyosin assembly and function. Muscle abnormalities associated with a defective tropomyosin allele were corrected by integrating the wild-type gene into germ line chromosomes. The transformation protocol permits application of directed mutagenesis techniques in investigations of contractile regulatory mechanisms.

scholarly journals Signal transduction, cell division, differentiation and development: towards unifying mechanisms for pattern formation in plants

2003 ◽  
Vol 15 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Marcelo Carnier Dornelas
Keyword(s):  
Signal Transduction ◽  
Cell Division ◽  
Pattern Formation ◽  
Cell Communication ◽  
Molecular Control ◽  
Form And Function ◽  
Plant Signal Transduction ◽  
Model Plant Arabidopsis Thaliana ◽  
Plant Form ◽  
And Function

The elaboration of plant form and function depends on the ability of a plant cell to divide and differentiate. The decisions of individual cells to enter the cell cycle, maintain proliferation competence, become quiescent, expand, differentiate, or die depend on cell-to-cell communication and on the perception of various signals. These signals can include hormones, nutrients, light, temperature, and internal positional and developmental cues. In recent years, progress has been made in understanding the molecular control of plant pattern formation, especially in the model plant Arabidopsis thaliana. Furthermore, specific genes have been found that are necessary for normal pattern formation and the control of the rates of cell division and differentiation. Cloning of these genes is revealing the molecular basis of plant pattern formation and the key players on plant signal transduction systems.

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