scholarly journals Emerging Insights into the Function of Kinesin-8 Proteins in Microtubule Length Regulation

Biomolecules ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Sanjay Shrestha ◽  
Mark Hazelbaker ◽  
Amber Yount ◽  
Claire Walczak
Keyword(s):  
Motor Activity ◽  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Structure And Function ◽  
Cellular Processes ◽  
Cellular Factors ◽  
Destabilizing Factors ◽  
Length Regulation ◽  
Mitotic Spindle Assembly ◽  
And Function

Proper regulation of microtubules (MTs) is critical for the execution of diverse cellular processes, including mitotic spindle assembly and chromosome segregation. There are a multitude of cellular factors that regulate the dynamicity of MTs and play critical roles in mitosis. Members of the Kinesin-8 family of motor proteins act as MT-destabilizing factors to control MT length in a spatially and temporally regulated manner. In this review, we focus on recent advances in our understanding of the structure and function of the Kinesin-8 motor domain, and the emerging contributions of the C-terminal tail of Kinesin-8 proteins to regulate motor activity and localization.

scholarly journals Emerging Insights into the Function of Kinesin-8 Proteins in Microtubule Length Regulation

2018 ◽  
Author(s):  
Sanjay Shrestha ◽  
Mark Hazelbaker ◽  
Amber L. Yount ◽  
Claire E. Walczak
Keyword(s):  
Motor Activity ◽  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Structure And Function ◽  
Cellular Processes ◽  
Cellular Factors ◽  
Destabilizing Factors ◽  
Length Regulation ◽  
Mitotic Spindle Assembly ◽  
And Function

Proper regulation of microtubules (MTs) is critical for the execution of diverse cellular processes, including mitotic spindle assembly and chromosome segregation. There are a multitude of cellular factors that regulate the dynamicity of MTs and play critical roles in mitosis. Members of the Kinesin-8 family of motor proteins act as MT-destabilizing factors to control MT length in a spatially and temporally regulated manner. In this review, we focus on recent advances in our understanding of the structure and function of the Kinesin-8 motor domain, and the emerging contributions of the C-terminal tail of Kinesin-8 proteins to regulate motor activity and localization.

scholarly journals The structure and function of centriolar rootlets

2021 ◽  
Vol 134 (16) ◽  
Author(s):  
Robert Mahen
Keyword(s):  
Cellular Function ◽  
Structure And Function ◽  
Cellular Systems ◽  
Macromolecular Assemblies ◽  
Cellular Processes ◽  
Holistic Understanding ◽  
Eukaryotic Organisms ◽  
And Function ◽  
Knockout Animals

ABSTRACT To gain a holistic understanding of cellular function, we must understand not just the role of individual organelles, but also how multiple macromolecular assemblies function collectively. Centrioles produce fundamental cellular processes through their ability to organise cytoskeletal fibres. In addition to nucleating microtubules, centrioles form lesser-known polymers, termed rootlets. Rootlets were identified over a 100 years ago and have been documented morphologically since by electron microscopy in different eukaryotic organisms. Rootlet-knockout animals have been created in various systems, providing insight into their physiological functions. However, the precise structure and function of rootlets is still enigmatic. Here, I consider common themes of rootlet function and assembly across diverse cellular systems. I suggest that the capability of rootlets to form physical links from centrioles to other cellular structures is a general principle unifying their functions in diverse cells and serves as an example of how cellular function arises from collective organellar activity.

scholarly journals Heterochromatin: Guardian of the Genome

2018 ◽  
Vol 34 (1) ◽  
pp. 265-288 ◽  
Author(s):  
Aniek Janssen ◽  
Serafin U. Colmenares ◽  
Gary H. Karpen
Keyword(s):  
Chromosome Segregation ◽  
Genome Stability ◽  
Constitutive Heterochromatin ◽  
Repetitive Sequences ◽  
Genome Integrity ◽  
Chromatin Domain ◽  
Cellular Processes ◽  
Eukaryotic Nucleus ◽  
And Function ◽  
Heterochromatin Structure

Constitutive heterochromatin is a major component of the eukaryotic nucleus and is essential for the maintenance of genome stability. Highly concentrated at pericentromeric and telomeric domains, heterochromatin is riddled with repetitive sequences and has evolved specific ways to compartmentalize, silence, and repair repeats. The delicate balance between heterochromatin epigenetic maintenance and cellular processes such as mitosis and DNA repair and replication reveals a highly dynamic and plastic chromatin domain that can be perturbed by multiple mechanisms, with far-reaching consequences for genome integrity. Indeed, heterochromatin dysfunction provokes genetic turmoil by inducing aberrant repeat repair, chromosome segregation errors, transposon activation, and replication stress and is strongly implicated in aging and tumorigenesis. Here, we summarize the general principles of heterochromatin structure and function, discuss the importance of its maintenance for genome integrity, and propose that more comprehensive analyses of heterochromatin roles in tumorigenesis will be integral to future innovations in cancer treatment.

scholarly journals Mitotic chromosome length scales in response to both cell and nuclear size

2015 ◽  
Vol 209 (5) ◽  
pp. 645-652 ◽  
Author(s):  
Anne-Marie Ladouceur ◽  
Jonas F. Dorn ◽  
Paul S. Maddox
Keyword(s):  
Cell Size ◽  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Mitotic Chromosome ◽  
Time Lapse ◽  
Chromosome Length ◽  
Nuclear Size ◽  
Multicellular Development ◽  
Length Regulation ◽  
Cellular Integrity

Multicellular development requires that cells reduce in size as a result of consecutive cell divisions without increase in embryo volume. To maintain cellular integrity, organelle size adapts to cell size throughout development. During mitosis, the longest chromosome arm must be shorter than half of the mitotic spindle for proper chromosome segregation. Using high-resolution time-lapse microscopy of living Caenorhabditis elegans embryos, we have quantified the relation between cell size and chromosome length. In control embryos, chromosome length scaled to cell size. Artificial reduction of cell size resulted in a shortening of chromosome length, following a trend predicted by measurements from control embryos. Disturbing the RAN (Ras-related nuclear protein)-GTP gradient decoupled nuclear size from cell size and resulted in chromosome scaling to nuclear size rather than cell size; smaller nuclei contained shorter chromosomes independent of cell size. In sum, quantitative analysis relating cell, nuclear, and chromosome size predicts two levels of chromosome length regulation: one through cell size and a second in response to nuclear size.

scholarly journals RNA interactomics: recent advances and remaining challenges

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1824 ◽  
Author(s):  
Brigitte Schönberger ◽  
Christoph Schaal ◽  
Richard Schäfer ◽  
Björn Voß
Keyword(s):  
High Throughput ◽  
Rna Structure ◽  
Living Cells ◽  
Structure And Function ◽  
Cellular Processes ◽  
Recent Advances ◽  
Regulatory Systems ◽  
Rna Duplexes ◽  
And Function

Tight regulation of cellular processes is key to the development of complex organisms but also vital for simpler ones. During evolution, different regulatory systems have emerged, among them RNA-based regulation that is carried out mainly by intramolecular and intermolecular RNA–RNA interactions. However, methods for the transcriptome-wide detection of these interactions were long unavailable. Recently, three publications described high-throughput methods to directly detect RNA duplexes in living cells. This promises to enable in-depth studies of RNA-based regulation and will narrow the gaps in our understanding of RNA structure and function. In this review, we highlight the benefits of these methods and their commonalities and differences and, in particular, point to methodological shortcomings that hamper their wider application. We conclude by presenting ideas for how to overcome these problems and commenting on the prospects we see in this area of research.

Driving chromosome segregation: lessons from the human and Drosophila centromere–kinetochore machinery

2010 ◽  
Vol 38 (6) ◽  
pp. 1667-1675 ◽  
Author(s):  
Bernardo Orr ◽  
Olga Afonso ◽  
Tália Feijão ◽  
Claudio E. Sunkel
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Genomic Stability ◽  
Mitotic Progression ◽  
Chromosomal Locus ◽  
Microtubule Attachment ◽  
Sister Chromatids ◽  
And Function ◽  
Drosophila Cells

The kinetochore is a complex molecular machine that serves as the interface between sister chromatids and the mitotic spindle. The kinetochore assembles at a particular chromosomal locus, the centromere, which is essential to maintain genomic stability during cell division. The kinetochore is a macromolecular puzzle of subcomplexes assembled in a hierarchical manner and fulfils three main functions: microtubule attachment, chromosome and sister chromatid movement, and regulation of mitotic progression though the spindle assembly checkpoint. In the present paper we compare recent results on the assembly, organization and function of the kinetochore in human and Drosophila cells and conclude that, although essential functions are highly conserved, there are important differences that might help define what is a minimal chromosome segregation machinery.

Brr2p RNA helicase with a split personality: insights into structure and function

2010 ◽  
Vol 38 (4) ◽  
pp. 1105-1109 ◽  
Author(s):  
Daniela Hahn ◽  
Jean D. Beggs
Keyword(s):  
Domain Architecture ◽  
Rna Helicase ◽  
Structure And Function ◽  
Mrna Splicing ◽  
Eye Disease ◽  
Rna Helicases ◽  
Cellular Processes ◽  
Biochemical Studies ◽  
Split Personality ◽  
And Function

RNA helicases are involved in many cellular processes. Pre-mRNA splicing requires eight different DExD/H-box RNA helicases, which facilitate spliceosome assembly and remodelling of the intricate network of RNA rearrangements that are central to the splicing process. Brr2p, one of the spliceosomal RNA helicases, stands out through its unusual domain architecture. In the present review we highlight the advances made by recent structural and biochemical studies that have important implications for the mechanism and regulation of Brr2p activity. We also discuss the involvement of human Brr2 in retinitis pigmentosa, a degenerative eye disease, and how its functions in splicing might connect to the molecular pathology of the disease.

Sign in / Sign up

Export Citation Format

Share Document