Pure thoughts with impure proteins: Permeabilized cell models of organelle motility

BioEssays ◽  
1993 ◽  
Vol 15 (11) ◽  
pp. 715-722 ◽  
Author(s):  
Joel A. Swanson
Keyword(s):  
Cell Models ◽  
Permeabilized Cell ◽  
Organelle Motility

scholarly journals Enhanced stability of microtubules enriched in detyrosinated tubulin is not a direct function of detyrosination level.

1988 ◽  
Vol 106 (1) ◽  
pp. 141-149 ◽  
Author(s):  
S Khawaja ◽  
G G Gundersen ◽  
J C Bulinski
Keyword(s):  
Relative Stability ◽  
Human Fibroblasts ◽  
Living Cells ◽  
Monkey Kidney ◽  
Cell Models ◽  
Carboxypeptidase A ◽  
Permeabilized Cell ◽  
Direct Function ◽  
Alpha Tubulin ◽  
Enhanced Stability

Interphase cultured monkey kidney (TC-7) cells contain distinct subsets of cellular microtubules (MTs) enriched in posttranslationally detyrosinated (Glu) or tyrosinated (Tyr) alpha tubulin (Gundersen, G. G., M. H. Kalnoski, and J. C. Bulinski. 1984. Cell. 38:779-789). To determine the relative stability of these subsets of MTs, we subjected TC-7 cells to treatments that slowly depolymerized MTs. We found Glu MTs to be more resistant than Tyr MTs to depolymerization by nocodazole in living cells, and to depolymerization by dilution in detergent-permeabilized cell models. However, in cold-treated cells, Glu and Tyr MTs did not differ significantly in their stability. Digestion of permeabilized cell models with pancreatic carboxypeptidase A, to generate Glu MTs from endogenous Tyr MTs, did not significantly alter the resistance of the endogenous Tyr MTs toward dilution-induced depolymerization. Furthermore, in human fibroblasts that contained no distinct Glu MTs, we observed a population of nocodazole-resistant MTs. These data suggest that Glu MTs possess enhanced stability against end-mediated depolymerization, yet detyrosination alone appears to be insufficient to confer this enhanced stability.

Radial movement of lysosomes along microtubules in permeabilized macrophages

1992 ◽  
Vol 103 (1) ◽  
pp. 201-209
Author(s):  
J.A. Swanson ◽  
A. Locke ◽  
P. Ansel ◽  
P.J. Hollenbeck
Keyword(s):  
Plasma Membranes ◽  
Cell Models ◽  
Permeabilized Cell ◽  
Murine Bone Marrow ◽  
Radial Movement ◽  
Selective Depletion ◽  
Cytoplasmic Microtubules ◽  
Phagocytic Response ◽  
Frustrated Phagocytosis

In murine bone marrow-derived macrophages, lysosomes often form tubulovesicular compartments, whose extended distribution in the cytoplasm depends on the integrity of cytoplasmic microtubules. When macrophages with fluorescently labeled lysosomes were plated onto coverslips opsonized with IgG, they engaged that surface in a phagocytic response (frustrated phagocytosis). The tubular lysosomal compartment of these cells collected in a central, perinuclear region, despite the continued presence of a radiating array of cytoplasmic microtubules. Using methods developed in the study of melanophores, we permeabilized macrophages engaged in frustrated phagocytosis, then re-activated lysosome extension along microtubules. Permeabilization was selective for plasma membranes, in that high molecular weight probes such as trypan blue or IgG could enter cells, while fluorescent probes previously loaded into lysosomes via endocytosis remained contained therein. Addition of 2 mM ATP, GTP or UTP to these permeabilized cell models produced centrifugal extension of tubular lysosomes. Selective depletion of ATP, using Escherichia coli glycerol kinase, inhibited ATP-dependent extension but not that which occurred with GTP or UTP, indicating that the mechanism of radial movement can use any of these three nucleotide triphosphates. Extension was independent of pH between 6.8 and 7.4, and was inhibited by AMP-PNP and by GMP-PNP. Depolymerization of cytoplasmic microtubules with nocodazole prevented subsequent ATP-inducible lysosome extension, whereas preincubation of cells with cytochalasin D did not inhibit the response. These results are consistent with the in vitro mechanochemical properties of kinesin (Cohn et al., 1989), and support earlier evidence, obtained in living cells, that kinesin is the mechanochemical motor of lysosome extension along microtubules in macrophages.

Contributions to the mechanisms of mitosis and roles of cytoplasmic microtubules from ultrastructural analyses of fungi

1978 ◽  
Vol 36 (2) ◽  
pp. 266-267
Author(s):  
I. Brent Heath
Keyword(s):  
Nuclear Envelope ◽  
Direct Application ◽  
Ultrastructural Analysis ◽  
General Interest ◽  
Research Results ◽  
Organelle Motility ◽  
Cytoplasmic Microtubules

Detailed ultrastructural analysis of fungal mitotic systems and cytoplasmic microtubules might be expected to contribute to a number of areas of general interest in addition to the direct application to the organisms of study. These areas include possibly fundamental general mechanisms of mitosis; evolution of mitosis; phylogeny of organisms; mechanisms of organelle motility and positioning; characterization of cellular aspects of microtubule properties and polymerization control features. This communication is intended to outline our current research results relating to selected parts of the above questions.Mitosis in the oomycetes Saprolegnia and Thraustotheca has been described previously. These papers described simple kinetochores and showed that the kineto- chores could probably be used as markers for the poorly defined chromosomes. Kineto- chore counts from serially sectioned prophase mitotic nuclei show that kinetochore replication precedes centriole replication to yield a single hemispherical array containing approximately the 4 n number of kinetochore microtubules diverging from the centriole associated "pocket" region of the nuclear envelope (Fig. 1).

Intronic miRNAs of Apoptosis Genes as Indicators of Cell Death

2019 ◽  
Vol 35 (6) ◽  
pp. 108-113
Author(s):  
J.A. Makarova ◽  
A.A. Poloznikov
Keyword(s):  
Breast Cancer ◽  
Cancer Cell Line ◽  
Ministry Of Education ◽  
Apoptosis Induction ◽  
Cell Models ◽  
Process Stage ◽  
Mature Micrornas ◽  
The Russian Federation ◽  
Apoptosis Level ◽  
Mcf 7

A method to assess the apoptosis level in cell models based on the analysis of the expression of micRNAs located in introns of apoptosis genes has been developed. Bioinformation analysis identified 536 genes associated with apoptosis; 30 of them contained 38 pre-microRNAs encoding 41 mature microRNAs. A significant change in the expression of hsa-miR-1244 and hsa-miR-4479 in response to apoptosis induction in the MCF-7 breast cancer cell line was revealed. A correlation was also found between the expression level of these miRNAs and the size of the primary tumor (process stage) in patients with breast cancer. apoptosis, microRNA, MCF7, breast cancer This work was supported by the Ministry of Education and Science of the Russian Federation (Project no. RFMEFI61618X0092).

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