scholarly journals Plant Kinesin-12: Localization Heterogeneity and Functional Implications

2019 ◽  
Vol 20 (17) ◽  
pp. 4213 ◽  
Author(s):  
Sabine Müller ◽  
Pantelis Livanos
Keyword(s):  
Cell Division ◽  
Current Knowledge ◽  
Male Gametophyte ◽  
Domain Architecture ◽  
Coiled Coil ◽  
Cell Plate ◽  
Cellular Level ◽  
Functional Diversification ◽  
Functional Implications ◽  
Directed Motility

Kinesin-12 family members are characterized by an N-terminal motor domain and the extensive presence of coiled-coil domains. Animal orthologs display microtubule plus-end directed motility, bundling of parallel and antiparallel microtubules, plus-end stabilization, and they play a crucial role in spindle assembly. In plants, kinesin-12 members mediate a number of developmental processes including male gametophyte, embryo, seedling, and seed development. At the cellular level, they participate in critical events during cell division. Several kinesin-12 members localize to the phragmoplast midzone, interact with isoforms of the conserved microtubule cross-linker MICROTUBULE-ASSOCIATED PROTEIN 65 (MAP65) family, and are required for phragmoplast stability and expansion, as well as for proper cell plate development. Throughout cell division, a subset of kinesin-12 reside, in addition or exclusively, at the cortical division zone and mediate the accurate guidance of the phragmoplast. This review aims to summarize the current knowledge on kinesin-12 in plants and shed some light onto the heterogeneous localization and domain architecture, which potentially conceals functional diversification.

scholarly journals The Caenorhabditis elegans protein SAS-5 forms large oligomeric assemblies critical for centriole formation

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Kacper B Rogala ◽  
Nicola J Dynes ◽  
Georgios N Hatzopoulos ◽  
Jun Yan ◽  
Sheng Kai Pong ◽  
...  
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Structural Analysis ◽  
Coiled Coil ◽  
Higher Order ◽  
Molecular Architecture ◽  
Eukaryotic Evolution ◽  
Centriole Duplication ◽  
Functional Implications

Centrioles are microtubule-based organelles crucial for cell division, sensing and motility. In Caenorhabditis elegans, the onset of centriole formation requires notably the proteins SAS-5 and SAS-6, which have functional equivalents across eukaryotic evolution. Whereas the molecular architecture of SAS-6 and its role in initiating centriole formation are well understood, the mechanisms by which SAS-5 and its relatives function is unclear. Here, we combine biophysical and structural analysis to uncover the architecture of SAS-5 and examine its functional implications in vivo. Our work reveals that two distinct self-associating domains are necessary to form higher-order oligomers of SAS-5: a trimeric coiled coil and a novel globular dimeric Implico domain. Disruption of either domain leads to centriole duplication failure in worm embryos, indicating that large SAS-5 assemblies are necessary for function in vivo.

scholarly journals When fate follows age: unequal centrosomes in asymmetric cell division

2014 ◽  
Vol 369 (1650) ◽  
pp. 20130466 ◽  
Author(s):  
Jose Reina ◽  
Cayetano Gonzalez
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Strong Correlation ◽  
Molecular Mechanisms ◽  
Asymmetric Cell Division ◽  
Current Knowledge ◽  
Cell Types ◽  
Functional Implications ◽  
Different Cell Types ◽  
Review Current

A strong correlation between centrosome age and fate has been reported in some stem cells and progenitors that divide asymmetrically. In some cases, such stereotyped centrosome behaviour is essential to endow stemness to only one of the two daughters, whereas in other cases causality is still uncertain. Here, we present the different cell types in which correlated centrosome age and fate has been documented, review current knowledge on the underlying molecular mechanisms and discuss possible functional implications of this process.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

Cell grouping and primary wall generations in the cambial zone, xylem, and phloem in Pinus

1968 ◽  
Vol 16 (2) ◽  
pp. 177 ◽  
Author(s):  
A Mahmood
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Secondary Wall ◽  
Radial Direction ◽  
Cell Plate ◽  
Tangential Direction ◽  
Primary Wall ◽  
Photographic Evidence ◽  
Secondary Wall Deposition ◽  
Cambial Zone

The use of the term cambium, or equivalent terms, in modern literature is discussed. The term cambial zone adopted in this paper includes the cambial initial and the dividing and enlarging cells. The tissue mother cell produced at each division of the initial produces a group of four cells in xylem or two cells in phloem. Theoretical constructs have been made for xylem and phloem production by associating the concepts that xylem and phloem are produced in alternate series of initial divisions and that a new primary wall is deposited around each daughter protoplast at each cell division. Correlations are derived from the theoretical constructs for the thickness of primary wall layers lying in the tangential direction and of those lying in the radial direction at progressive histological levels. Deductions from theoretical constructs are made when the initial is producing xylem, when it changes its polarity from xylem to phloem production, and when the reverse change occurs. Most of the theoretical deductions are supported by photographic evidence. The chief point of this study is the demonstration of generations (multiplicity) of primary parental walls. The term intercellular material proposed in this paper includes the cell plate plus any remnants of ancestral primary walls between the current primary walls surrounding the adjacent protoplasts. This term is still applicable to cells where secondary wall deposition is taking place or has been completed.

scholarly journals Glycosylation of matrix metalloproteases and tissue inhibitors: present state, challenges and opportunities

2016 ◽  
Vol 473 (11) ◽  
pp. 1471-1482 ◽  
Author(s):  
Lise Boon ◽  
Estefania Ugarte-Berzal ◽  
Jennifer Vandooren ◽  
Ghislain Opdenakker
Keyword(s):  
Matrix Metalloproteinases ◽  
Present State ◽  
Cellular Localization ◽  
Current Knowledge ◽  
Matrix Metalloproteases ◽  
Inhibitor Binding ◽  
Attachment Sites ◽  
Functional Aspects ◽  
Functional Implications ◽  
Challenges And Opportunities

Current knowledge about the glycosylation of matrix metalloproteinases (MMPs) and the inhibitors of metalloproteinases (TIMPs) is reviewed. Whereas structural and functional aspects of the glycobiology of many MMPs is unknown, research on MMP-9 and MMP-14 glycosylation reveals important functional implications, such as altered inhibitor binding and cellular localization. This, together with the fact that MMPs contain conserved and many potential attachment sites for N-linked and O-linked oligosaccharides, proves the need for further studies on MMP glycobiology.

The bryophytes Physcomitrium patens and Marchantia polymorpha as model systems for studying evolutionary cell and developmental biology in plants

2021 ◽  
Author(s):  
Satoshi Naramoto ◽  
Yuki Hata ◽  
Tomomichi Fujita ◽  
Junko Kyozuka
Keyword(s):  
Developmental Biology ◽  
Cell Division ◽  
Current Knowledge ◽  
Flowering Plants ◽  
Model Systems ◽  
Marchantia Polymorpha ◽  
Special Focus ◽  
Cellular Mechanisms ◽  
Regulatory Pathways ◽  
Biological Studies

Abstract Bryophytes are non-vascular spore-forming plants. Unlike in flowering plants, the gametophyte (haploid) generation of bryophytes dominates the sporophyte (diploid) generation. A comparison of bryophytes with flowering plants allows us to answer some fundamental questions raised in evolutionary cell and developmental biology. The moss Physcomitrium patens was the first bryophyte with a sequenced genome. Many cell and developmental studies have been conducted in this species using gene targeting by homologous recombination. The liverwort Marchantia polymorpha has recently emerged as an excellent model system with low genomic redundancy in most of its regulatory pathways. With the development of molecular genetic tools such as efficient genome editing, both P. patens and M. polymorpha have provided many valuable insights. Here, we review these advances, with a special focus on polarity formation at the cell and tissue levels. We examine current knowledge regarding the cellular mechanisms of polarized cell elongation and cell division, including symmetric and asymmetric cell division. We also examine the role of polar auxin transport in mosses and liverworts. Finally, we discuss the future of evolutionary cell and developmental biological studies in plants.

scholarly journals Acute Myeloid Leukemia Stem Cells: The Challenges of Phenotypic Heterogeneity

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3742
Author(s):  
Marlon Arnone ◽  
Martina Konantz ◽  
Pauline Hanns ◽  
Anna M. Paczulla Stanger ◽  
Sarah Bertels ◽  
...  
Keyword(s):  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Current Knowledge ◽  
Phenotypic Variability ◽  
Cellular Level ◽  
Patient Specific ◽  
Heterogeneous Landscape ◽  
Cells Of Origin ◽  
Acute Myeloid

Patients suffering from acute myeloid leukemia (AML) show highly heterogeneous clinical outcomes. Next to variabilities in patient-specific parameters influencing treatment decisions and outcome, this is due to differences in AML biology. In fact, different genetic drivers may transform variable cells of origin and co-exist with additional genetic lesions (e.g., as observed in clonal hematopoiesis) in a variety of leukemic (sub)clones. Moreover, AML cells are hierarchically organized and contain subpopulations of more immature cells called leukemic stem cells (LSC), which on the cellular level constitute the driver of the disease and may evolve during therapy. This genetic and hierarchical complexity results in a pronounced phenotypic variability, which is observed among AML cells of different patients as well as among the leukemic blasts of individual patients, at diagnosis and during the course of the disease. Here, we review the current knowledge on the heterogeneous landscape of AML surface markers with particular focus on those identifying LSC, and discuss why identification and targeting of this important cellular subpopulation in AML remains challenging.

scholarly journals Divisome under Construction: Distinct Domains of the Small Membrane Protein FtsB Are Necessary for Interaction with Multiple Cell Division Proteins

2009 ◽  
Vol 191 (8) ◽  
pp. 2815-2825 ◽  
Author(s):  
Mark D. Gonzalez ◽  
Jon Beckwith
Keyword(s):  
Cell Division ◽  
Membrane Proteins ◽  
Protein Interactions ◽  
Cell Envelope ◽  
Coiled Coil ◽  
Main Function ◽  
Protein Protein Interactions ◽  
Molecular Scaffold ◽  
C Terminus ◽  
Under Construction

ABSTRACT Cell division in bacteria requires the coordinated action of a set of proteins, the divisome, for proper constriction of the cell envelope. Multiple protein-protein interactions are required for assembly of a stable divisome. Within the Escherichia coli divisome is a conserved subcomplex of inner membrane proteins, the FtsB/FtsL/FtsQ complex, which is necessary for linking the upstream division proteins, which are predominantly cytoplasmic, with the downstream division proteins, which are predominantly periplasmic. FtsB and FtsL are small bitopic membrane proteins with predicted coiled-coil motifs, which themselves form a stable subcomplex that can recruit downstream division proteins independently of FtsQ; however, the details of how FtsB and FtsL interact together and with other proteins remain to be characterized. Despite the small size of FtsB, we identified separate interaction domains of FtsB that are required for interaction with FtsL and FtsQ. The N-terminal half of FtsB is necessary for interaction with FtsL and sufficient, when in complex with FtsL, for recruitment of downstream division proteins, while a portion of the FtsB C terminus is necessary for interaction with FtsQ. These properties of FtsB support the proposal that its main function is as part of a molecular scaffold to allow for proper formation of the divisome.

The Role of Free Radicals in Traumatic Brain Injury

2012 ◽  
Vol 15 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Karen M. O’Connell ◽  
Marguerite T. Littleton-Kearney
Keyword(s):  
Traumatic Brain Injury ◽  
Free Radicals ◽  
Free Radical ◽  
Brain Injury ◽  
Current Knowledge ◽  
Cellular Level ◽  
Secondary Brain Injury ◽  
Secondary Injury ◽  
The Military

Traumatic brain injury (TBI) is a significant cause of death and disability in both the civilian and the military populations. The primary impact causes initial tissue damage, which initiates biochemical cascades, known as secondary injury, that expand the damage. Free radicals are implicated as major contributors to the secondary injury. Our review of recent rodent and human research reveals the prominent role of the free radicals superoxide anion, nitric oxide, and peroxynitrite in secondary brain injury. Much of our current knowledge is based on rodent studies, and the authors identified a gap in the translation of findings from rodent to human TBI. Rodent models are an effective method for elucidating specific mechanisms of free radical-induced injury at the cellular level in a well-controlled environment. However, human TBI does not occur in a vacuum, and variables controlled in the laboratory may affect the injury progression. Additionally, multiple experimental TBI models are accepted in rodent research, and no one model fully reproduces the heterogeneous injury seen in humans. Free radical levels are measured indirectly in human studies based on assumptions from the findings from rodent studies that use direct free radical measurements. Further study in humans should be directed toward large samples to validate the findings in rodent studies. Data obtained from these studies may lead to more targeted treatment to interrupt the secondary injury cascades.

RADIATION, THE CELLULAR APPROACH

1960 ◽  
Vol 38 (3) ◽  
pp. 320-325
Author(s):  
Gordon M. Clark ◽  
Donald G. Baker
Keyword(s):  
Cell Division ◽  
Chemical Synthesis ◽  
Dose Rate ◽  
Current Trend ◽  
Biological Action ◽  
Cellular Level ◽  
Chromosome Breaks ◽  
Effect Of Oxygen ◽  
Almost All ◽  
Dose Rate Effect

The basic biological action of radiation must initially involve particular cells. The sensitivity of various cells differs but some of the differences may be due to a dose-rate effect. When cells are irradiated with doses in the lethal range, inhibition of cell division occurs. A notable feature of mitotic inhibition is that it depends not only on dose but on dose rate. Chromosome breaks produced in cells may be a visible manifestation of an interruption in chemical synthesis produced by the passage of ionizing particles. The effect of oxygen is apparently of primary importance in biological changes produced by irradiation. Almost all are decreased in its absence. The current trend in research on the cellular level is towards determining the more obscure injuries which cannot be seen under the microscope.

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