scholarly journals Partitioning and Exocytosis of Secretory Granules during Division of PC12 Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Nickolay Vassilev Bukoreshtliev ◽  
Erlend Hodneland ◽  
Tilo Wolf Eichler ◽  
Patricia Eifart ◽  
Amin Rustom ◽  
...  
Keyword(s):  
Cell Division ◽  
Pc12 Cells ◽  
Secretory Granules ◽  
Time Lapse ◽  
Intercellular Bridge ◽  
Time Lapse Microscopy ◽  
Interphase Cells ◽  
Molecular Machinery ◽  
Spindle Microtubules ◽  
Single Granule

The biogenesis, maturation, and exocytosis of secretory granules in interphase cells have been well documented, whereas the distribution and exocytosis of these hormone-storing organelles during cell division have received little attention. By combining ultrastructural analyses and time-lapse microscopy, we here show that, in dividing PC12 cells, the prominent peripheral localization of secretory granules is retained during prophase but clearly reduced during prometaphase, ending up with only few peripherally localized secretory granules in metaphase cells. During anaphase and telophase, secretory granules exhibited a pronounced movement towards the cell midzone and, evidently, their tracks colocalized with spindle microtubules. During cytokinesis, secretory granules were excluded from the midbody and accumulated at the bases of the intercellular bridge. Furthermore, by measuring exocytosis at the single granule level, we showed, that during all stages of cell division, secretory granules were competent for regulated exocytosis. In conclusion, our data shed new light on the complex molecular machinery of secretory granule redistribution during cell division, which facilitates their release from the F-actin-rich cortex and active transport along spindle microtubules.

scholarly journals Granule exocytosis is required for platelet spreading: differential sorting of α-granules expressing VAMP-7

Blood ◽  
2012 ◽  
Vol 120 (1) ◽  
pp. 199-206 ◽  
Author(s):  
Christian G. Peters ◽  
Alan D. Michelson ◽  
Robert Flaumenhaft
Keyword(s):  
Immunofluorescence Microscopy ◽  
Time Lapse ◽  
Granule Exocytosis ◽  
Time Lapse Microscopy ◽  
Gray Platelet Syndrome ◽  
Platelet Spreading ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Discrete Functions ◽  
Single Granule

Abstract There has been recent controversy as to whether platelet α-granules represent a single granule population or are composed of different subpopulations that serve discrete functions. To address this question, we evaluated the localization of vesicle-associated membrane proteins (VAMPs) in spread platelets to determine whether platelets actively sort a specific subpopulation of α-granules to the periphery during spreading. Immunofluorescence microscopy demonstrated that granules expressing VAMP-3 and VAMP-8 localized to the central granulomere of spread platelets along with the granule cargos von Willebrand factor and serotonin. In contrast, α-granules expressing VAMP-7 translocated to the periphery of spread platelets along with the granule cargos TIMP2 and VEFG. Time-lapse microscopy demonstrated that α-granules expressing VAMP-7 actively moved from the granulomere to the periphery during spreading. Platelets from a patient with gray platelet syndrome lacked α-granules and demonstrated only minimal spreading. Similarly, spreading was impaired in platelets obtained from Unc13dJinx mice, which are deficient in Munc13-4 and have an exocytosis defect. These studies identify a new α-granule subtype expressing VAMP-7 that moves to the periphery during spreading, supporting the premise that α-granules are heterogeneous and demonstrating that granule exocytosis is required for platelet spreading.

scholarly journals The budding yeast Ipl1/Aurora protein kinase regulates mitotic spindle disassembly

2003 ◽  
Vol 160 (3) ◽  
pp. 329-339 ◽  
Author(s):  
Stéphanie Buvelot ◽  
Sean Y. Tatsutani ◽  
Danielle Vermaak ◽  
Sue Biggins
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Kinase Activity ◽  
Budding Yeast ◽  
Genomic Stability ◽  
Time Lapse ◽  
Time Lapse Microscopy ◽  
Spindle Disassembly ◽  
Spindle Midzone ◽  
Spindle Microtubules

Ipl1p is the budding yeast member of the Aurora family of protein kinases, critical regulators of genomic stability that are required for chromosome segregation, the spindle checkpoint, and cytokinesis. Using time-lapse microscopy, we found that Ipl1p also has a function in mitotic spindle disassembly that is separable from its previously identified roles. Ipl1–GFP localizes to kinetochores from G1 to metaphase, transfers to the spindle after metaphase, and accumulates at the spindle midzone late in anaphase. Ipl1p kinase activity increases at anaphase, and ipl1 mutants can stabilize fragile spindles. As the spindle disassembles, Ipl1p follows the plus ends of the depolymerizing spindle microtubules. Many Ipl1p substrates colocalize with Ipl1p to the spindle midzone, identifying additional proteins that may regulate spindle disassembly. We propose that Ipl1p regulates both the kinetochore and interpolar microtubule plus ends to regulate its various mitotic functions.

scholarly journals Cell division and cell shape patterns during migration of the embryonic chick neural crest revealed by in vivo time-lapse microscopy

2010 ◽  
Vol 344 (1) ◽  
pp. 473
Author(s):  
Dennis A. Ridenour ◽  
Katherine W. Prather ◽  
Rebecca McLennan ◽  
Zachary Warren ◽  
Paul M. Kulesa
Keyword(s):  
Cell Division ◽  
Neural Crest ◽  
Cell Shape ◽  
Time Lapse ◽  
Embryonic Chick ◽  
Time Lapse Microscopy

scholarly journals Analysis of Cell–Cell Bridges in Haloferax volcanii Using Electron Cryo-Tomography Reveal a Continuous Cytoplasm and S-Layer

2021 ◽  
Vol 11 ◽  
Author(s):  
Shamphavi Sivabalasarma ◽  
Hanna Wetzel ◽  
Phillip Nußbaum ◽  
Chris van der Does ◽  
Morgan Beeby ◽  
...  
Keyword(s):  
Halophilic Archaea ◽  
Time Lapse ◽  
Intercellular Bridge ◽  
Helical Structures ◽  
Macromolecular Complexes ◽  
Time Lapse Microscopy ◽  
A Cell ◽  
Cellular Components ◽  
Shed Light ◽  
Cell Cell

Halophilic archaea have been proposed to exchange DNA and proteins using a fusion-based mating mechanism. Scanning electron microscopy previously suggested that mating involves an intermediate state, where cells are connected by an intercellular bridge. To better understand this process, we used electron cryo-tomography (cryoET) and fluorescence microscopy to visualize cells forming these intercellular bridges. CryoET showed that the observed bridges were enveloped by an surface layer (S-layer) and connected mating cells via a continuous cytoplasm. Macromolecular complexes like ribosomes and unknown thin filamentous helical structures were visualized in the cytoplasm inside the bridges, demonstrating that these bridges can facilitate exchange of cellular components. We followed formation of a cell–cell bridge by fluorescence time-lapse microscopy between cells at a distance of 1.5 μm. These results shed light on the process of haloarchaeal mating and highlight further mechanistic questions.

MSA-35: a protein identified by human autoantibodies that colocalizes with microtubules

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1115-1122 ◽  
Author(s):  
J. B. Rattner ◽  
T. Wang ◽  
G. Mack ◽  
L. Martin ◽  
M. J. Fritzler
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Hela Cells ◽  
Temporal Distribution ◽  
Mitotic Arrest ◽  
Spatial And Temporal Distribution ◽  
Intercellular Bridge ◽  
Centrosome Separation ◽  
Interphase Cells ◽  
Low Levels

We have identified a putative 35-kilodalton protein that colocalizes with microtubules and displays a unique spatial and temporal distribution during the cell cycle of HeLa cells. This protein has been given the designation MSA-35. MSA-35 first appears in association with microtubules and centrosomes of interphase cells exhibiting centrosome separation as a prelude to cell division. This protein is found in conjunction with kinetochore microtubules throughout their appearance. MSA-35 transiently associates with interpolar microtubules following anaphase and the pattern of MSA-35 reactivity in telophase cells suggests that there are at least seven domains within the intercellular bridge. The distribution of MSA-35 during and following recovery from mitotic arrest with nocodazole suggest that it is also present at low levels in interphase cells, can associate with interphase centrosomes, and colocalizes with nascent microtubules. The complex spatial and temporal distribution of MSA-35 indicates that it may be necessary for a series of events in the mitotic process such as the bundling of microtubules.Key words: mitosis, autoantibodies, spindle.

scholarly journals The Cockayne syndrome group A and B proteins are part of a ubiquitin–proteasome degradation complex regulating cell division

2020 ◽  
Vol 117 (48) ◽  
pp. 30498-30508
Author(s):  
Elena Paccosi ◽  
Federico Costanzo ◽  
Michele Costantino ◽  
Alessio Balzerano ◽  
Laura Monteonofrio ◽  
...  
Keyword(s):  
Dna Repair ◽  
Cell Division ◽  
Degradation Process ◽  
Cockayne Syndrome ◽  
Intercellular Bridge ◽  
Proteasome Degradation ◽  
Daughter Cells ◽  
Multinucleated Cells ◽  
Ubiquitin Proteasome ◽  
Molecular Machinery

Cytokinesis is monitored by a molecular machinery that promotes the degradation of the intercellular bridge, a transient protein structure connecting the two daughter cells. Here, we found that CSA and CSB, primarily defined as DNA repair factors, are located at the midbody, a transient structure in the middle of the intercellular bridge, where they recruit CUL4 and MDM2 ubiquitin ligases and the proteasome. As a part of this molecular machinery, CSA and CSB contribute to the ubiquitination and the degradation of proteins such as PRC1, the Protein Regulator of Cytokinesis, to ensure the correct separation of the two daughter cells. Defects in CSA or CSB result in perturbation of the abscission leading to the formation of long intercellular bridges and multinucleated cells, which might explain part of the Cockayne syndrome phenotypes. Our results enlighten the role played by CSA and CSB as part of a ubiquitin/proteasome degradation process involved in transcription, DNA repair, and cell division.

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