scholarly journals The Concentration of Nuf, a Rab11 Effector, at the Microtubule-organizing Center Is Cell Cycle–regulated, Dynein-dependent, and Coincides with Furrow Formation

2007 ◽  
Vol 18 (9) ◽  
pp. 3313-3322 ◽  
Author(s):  
Blake Riggs ◽  
Barbara Fasulo ◽  
Anne Royou ◽  
Sarah Mische ◽  
Jian Cao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Small Gtpase ◽  
Drosophila Embryo ◽  
Microtubule Organizing Center ◽  
Recycling Endosome ◽  
Actin Organization ◽  
Protein Levels ◽  
Nuclear Fallout ◽  
Early Drosophila Embryo ◽  
Organizing Center

Animal cytokinesis relies on membrane addition as well as acto-myosin–based constriction. Recycling endosome (RE)-derived vesicles are a key source of this membrane. Rab11, a small GTPase associated with the RE and involved in vesicle targeting, is required for elongation of the cytokinetic furrow. In the early Drosophila embryo, Nuclear-fallout (Nuf), a Rab11 effector, promotes vesicle-mediated membrane delivery and actin organization at the invaginating furrow. Although Rab11 maintains a relatively constant localization at the microtubule-organizing center (MTOC), Nuf is present at the MTOC only during the phases of the cell cycle in which furrow invagination occurs. We demonstrate that Nuf protein levels remain relatively constant throughout the cell cycle, suggesting that Nuf is undergoing cycles of concentration and dispersion from the MTOC. Microtubules, but not microfilaments, are required for proper MTOC localization of Nuf and Rab11. The MTOC localization of Nuf also relies on Dynein. Immunoprecipitation experiments demonstrate that Nuf and Dynein physically interact. In accord with these findings, and in contrast to previous reports, we demonstrate that microtubules are required for proper metaphase furrow formation. We propose that the cell cycle–regulated, Dynein-dependent recruitment of Nuf to the MTOC influences the timing of RE-based vesicle delivery to the invaginating furrows.

CEP110 and ninein are located in a specific domain of the centrosome associated with centrosome maturation

2002 ◽  
Vol 115 (9) ◽  
pp. 1825-1835 ◽  
Author(s):  
Young Y. Ou ◽  
Gary J. Mack ◽  
Meifeng Zhang ◽  
Jerome B. Rattner
Keyword(s):  
Cell Cycle ◽  
Protein Interactions ◽  
Protein Function ◽  
Similar Distribution ◽  
Microtubule Organizing Center ◽  
Specific Domain ◽  
The Reformation ◽  
Mother And Daughter ◽  
Organizing Center ◽  
Pericentriolar Material

The mammalian centrosome consists of a pair of centrioles surrounded by pericentriolar material (PCM). The architecture and composition of the centrosome, especially the PCM, changes during the cell cycle. Recently, a subset of PCM proteins have been shown to be arranged in a tubular conformation with an open and a closed end within the centrosome. The presence of such a specific configuration can be used as a landmark for mapping proteins in both a spatial and a temporal fashion. Such mapping studies can provide information about centrosome organization, protein dynamics,protein-protein interactions as well as protein function. In this study, the centrosomal proteins CEP110 and ninein were mapped in relationship to the tubular configuration. Both proteins were found to exhibit a similar distribution pattern. In the mother centrosome, they were found at both ends of the centrosome tube, including the site of centrosome duplication. However,in the daughter centrosome they were present only at the closed end. At the closed end of the mother and daughter centrosome tube, both CEP110 and ninein co-localized with the centriolar protein CEP250/c-Nap1, which confirms ninein's centriole association and places CEP110 in association with this structure. Importantly, the appearance of CEP110 and ninein at the open end of the daughter centrosome occurred during the telophase-G1 transition of the next cell cycle, concomitant with the maturation of the daughter centrosome into a mother centrosome. Microinjection of antibodies against either CEP110 or ninein into metaphase HeLa cells disrupted the reformation of the tubular conformation of proteins within the centrosome following cell division and consequently led to dispersal of centrosomal material throughout the cytosol. Further, microinjection of antibodies to either CEP110 or ninein into metaphase PtK2 cells not only disrupted the tubular configuration within the centrosome but also affected the centrosome's ability to function as a microtubule organizing center (MTOC). This MTOC function was also disrupted when the antibodies were injected into postmitotic cells. Taken together, our results indicate that: (1) a population of CEP110 and ninein is located in a specific domain within the centrosome, which corresponds to the open end of the centrosome tube and is the site of protein addition associated with maturation of a daughter centrosome into a mother centrosome; and (2) the addition of CEP110 and ninein are essential for the reformation of specific aspects of the interphase centrosome architecture following mitosis as well as being required for the centrosome to function as a MTOC.

scholarly journals Radial F-actin Organization During Early Neuronal Development

2018 ◽  
Author(s):  
Durga Praveen Meka ◽  
Robin Scharrenberg ◽  
Bing Zhao ◽  
Theresa König ◽  
Irina Schaefer ◽  
...  
Keyword(s):  
Neuronal Development ◽  
Super Resolution ◽  
Actin Dynamics ◽  
Cell Periphery ◽  
Microtubule Organizing Center ◽  
Actin Organization ◽  
Organizing Center ◽  
Super Resolution Microscopy ◽  
Radial Organization

AbstractThe centrosome is thought to be the major neuronal microtubule-organizing center (MTOC) in early neuronal development, producing microtubules with a radial organization. In addition, albeit in vitro, recent work showed that isolated centrosomes could serve as an actin-organizing center (Farina et al., 2016), raising the possibility that neuronal development may, in addition, require a centrosome-based actin radial organization. Here we report, using super-resolution microscopy and live-cell imaging, F-actin organization around the centrosome with dynamic F-actin aster-like structures with F-actin fibers extending and retracting actively. Photoconversion/photoactivation experiments and molecular manipulations of F-actin stability reveal a robust flux of somatic F-actin towards the cell periphery. Finally, we show that somatic F-actin intermingles with centrosomal PCM-1 satellites. Knockdown of PCM-1 and disruption of centrosomal activity not only affect F-actin dynamics near the centrosome but also in distal growth cones. Collectively the data show a radial F-actin organization during early neuronal development, which might be a cellular mechanism for providing peripheral regions with a fast and continuous source of actin polymers; hence sustaining initial neuronal development.

scholarly journals The cell cycle-dependent localization of the CP190 centrosomal protein is determined by the coordinate action of two separable domains.

1995 ◽  
Vol 131 (5) ◽  
pp. 1261-1273 ◽  
Author(s):  
K Oegema ◽  
W G Whitfield ◽  
B Alberts
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Nuclear Localization ◽  
Fusion Proteins ◽  
Drosophila Embryo ◽  
Dependent Manner ◽  
Fluorescence Confocal Microscopy ◽  
Early Drosophila Embryo ◽  
A Cell ◽  
Cycle Dependent

CP190, a protein of 1,096 amino acids from Drosophila melanogaster, oscillates in a cell cycle-specific manner between the nucleus during interphase, and the centrosome during mitosis. To characterize the regions of CP190 responsible for its dynamic behavior, we injected rhodamine-labeled fusion proteins spanning most of CP190 into early Drosophila embryos, where their localizations were characterized using time-lapse fluorescence confocal microscopy. A single bipartite 19-amino acid nuclear localization signal was detected that causes nuclear localization. Robust centrosomal localization is conferred by a separate region of 124 amino acids; two adjacent, nonoverlapping fusion proteins containing distinct portions of this region show weaker centrosomal localization. Fusion proteins that contain both nuclear and centrosomal localization sequences oscillate between the nucleus and the centrosome in a manner identical to native CP190. Fusion proteins containing only the centrosome localization sequence are found at centrosomes throughout the cell cycle, suggesting that CP190 is actively recruited away from the centrosome by its movement into the nucleus during interphase. Both native and bacterially expressed CP190 cosediment with microtubules in vitro. Tests with fusion proteins show that the domain responsible for microtubule binding overlaps the domain required for centrosomal localization. CP60, a protein identified by its association with CP190, also localizes to centrosomes and to nuclei in a cell cycle-dependent manner. Experiments in which colchicine is used to depolymerize microtubules in the early Drosophila embryo demonstrate that both CP190 and CP60 are able to attain and maintain their centrosomal localization in the absence of microtubules.

scholarly journals The centriolar satellite protein Cfap53/Ccdc11 facilitates the formation of the first zygotic microtubule organizing center in the zebrafish embryo

2020 ◽  
Author(s):  
Sven Willekers ◽  
Federico Tessadori ◽  
Babet van der Vaart ◽  
Heiko Henning ◽  
Riccardo Stucchi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Danio Rerio ◽  
Mitotic Spindle ◽  
Sperm Cell ◽  
Zebrafish Embryo ◽  
Animal Species ◽  
Microtubule Organizing Center ◽  
Microtubule Network ◽  
Cell Divisions ◽  
Organizing Center

AbstractIn embryos from most animal species a zygotic centrosome is assembled by the centriole derived from the sperm cell and pericentriolar proteins present in the oocyte. This zygotic centrosome acts as a microtubule organizing center (MTOC) to assemble the mitotic spindle in the first and all subsequent cell divisions. As MTOC formation has been studied mainly in adult cells, very little is known about the formation of the first zygotic MTOC. Here we find that zebrafish (Danio rerio) embryos lacking maternal or paternal Cfap53, a centriolar satellite protein, arrest during the first cell cycle due to a failure in proper formation of the mitotic spindle. During the first cell cycle Cfap53 co-localizes with γ-tubulin and other centrosomal and centriolar satellite proteins to the very large MTOC. Furthermore, we find that γ-tubulin localization to the MTOC is impaired in the absence of Cfap53 or when the microtubule network is disrupted. Based on these results we propose a model in which maternal and paternal Cfap53 participates in the organization of the first zygotic MTOC of the embryo. Once the zygotic MTOC is formed, Cfap53 is dispensable for MTOC formation and integrity in subsequent cell divisions.

scholarly journals Epstein-Barr Virus Thymidine Kinase Is a Centrosomal Resident Precisely Localized to the Periphery of Centrioles

2007 ◽  
Vol 81 (12) ◽  
pp. 6523-6535 ◽  
Author(s):  
Michael B. Gill ◽  
Jeffery L. Kutok ◽  
Joyce D. Fingeroth
Keyword(s):  
Cell Cycle ◽  
Thymidine Kinase ◽  
Epstein Barr Virus ◽  
Cell Types ◽  
Regulatory Function ◽  
Antigenic Peptides ◽  
Microtubule Organizing Center ◽  
Barr Virus ◽  
Organizing Center ◽  
Epstein Barr

ABSTRACT The thymidine kinase (TK) encoded by Epstein-Barr virus (EBV) differs not only from that of the alphaherpesviruses but also from that of the gamma-2 herpesvirus subfamily. Because cellular location is frequently a determinant of regulatory function, to gain insight into additional role(s) of EBV TK and to uncover how the lymphocryptovirus and rhadinovirus enzymes differ, the subcellular localizations of EBV TK and the related cercopithecine herpesvirus-15 TK were investigated. We show that in contrast to those of the other family members, the gamma-1 herpesvirus TKs localize to the centrosome and even more precisely to the periphery of the centriole, tightly encircling the tubulin-rich centrioles in a microtubule-independent fashion. Centrosomal localization is observed in diverse cell types and occurs whether the protein is expressed independently or in the context of lytic EBV infection. Surprisingly, analysis of mutants revealed that the unique N-terminal domain was not critical for targeting to the centrosome, but rather, peptide sequences located C terminal to this domain were key. This is the first herpesvirus protein documented to reside in the centrosome, or microtubule-organizing center, an amembranous organelle that regulates the structural biology of the cell cycle through control of chromosome separation and cytokinesis. More recently, proteasome-mediated degradation of cell cycle regulatory proteins, production and loading of antigenic peptides onto HLA molecules, and transient homing of diverse virion proteins required for entry and/or egress have been shown to be coordinated at the centrosome. Potential implications of centrosomal localization for EBV TK function are discussed.

scholarly journals A two-step mechanism for the inactivation of microtubule organizing center function at the centrosome

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jérémy Magescas ◽  
Jenny C Zonka ◽  
Jessica L Feldman
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Outer Sphere ◽  
Microtubule Organizing Center ◽  
C Elegans ◽  
Mitotic Kinases ◽  
Pulling Forces ◽  
Organizing Center ◽  
Pericentriolar Material ◽  
Step Mechanism

The centrosome acts as a microtubule organizing center (MTOC), orchestrating microtubules into the mitotic spindle through its pericentriolar material (PCM). This activity is biphasic, cycling through assembly and disassembly during the cell cycle. Although hyperactive centrosomal MTOC activity is a hallmark of some cancers, little is known about how the centrosome is inactivated as an MTOC. Analysis of endogenous PCM proteins in C. elegans revealed that the PCM is composed of partially overlapping territories organized into an inner and outer sphere that are removed from the centrosome at different rates and using different behaviors. We found that phosphatases oppose the addition of PCM by mitotic kinases, ultimately catalyzing the dissolution of inner sphere PCM proteins at the end of mitosis. The nature of the PCM appears to change such that the remaining aging PCM outer sphere is mechanically ruptured by cortical pulling forces, ultimately inactivating MTOC function at the centrosome.

scholarly journals Mutated in Colorectal Cancer (MCC): a centrosomal protein that relocalizes to the ncMTOC during intestinal cell differentiation

2021 ◽  
Author(s):  
Lucian B. Tomaz ◽  
Bernard A. Liu ◽  
Sheena L.M. Ong ◽  
Ee Kim Tan ◽  
Meroshini M ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Intestinal Epithelium ◽  
Coiled Coil ◽  
Human Colon ◽  
Intestinal Cell ◽  
Microtubule Organizing Center ◽  
Human Colon Cancer ◽  
Protein Levels ◽  
Organizing Center ◽  
Casein Kinases

Mutated in Colorectal Cancer (MCC) encodes a coiled-coil protein implicated, as its name suggests, in the pathogenesis of hereditary human colon cancer. To date, however, the contributions of MCC to intestinal homeostasis remain unclear. Here, we examine the subcellular localization of MCC, both at the mRNA and protein levels, in the adult intestinal epithelium. Our findings reveal that Mcc transcripts are restricted to proliferating crypt cells, including Lgr5+ stem cells, and that Mcc protein is distinctly associated with the centrosome in these cells. Upon intestinal cellular differentiation, Mcc is redeployed to the non-centrosomal microtubule organizing center (ncMTOC) at the apical domain of villus cells. Using intestinal organoids, we show that the shuttling of the Mcc protein depends on phosphorylation by Casein Kinases 1δ/ε, which are critical modulators of WNT signaling. Together, our findings support a putative role for MCC in establishing and maintaining the cellular architecture of the intestinal epithelium as a component of both the centrosome and ncMTOC.

scholarly journals Breaking the ties that bind: New advances in centrosome biology

2012 ◽  
Vol 197 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Balca R. Mardin ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Cancer Cells ◽  
Recent Work ◽  
Genomic Instability ◽  
Centrosome Duplication ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
Centrosome Separation ◽  
Organizing Center ◽  
Pericentriolar Material

The centrosome, which consists of two centrioles and the surrounding pericentriolar material, is the primary microtubule-organizing center (MTOC) in animal cells. Like chromosomes, centrosomes duplicate once per cell cycle and defects that lead to abnormalities in the number of centrosomes result in genomic instability, a hallmark of most cancer cells. Increasing evidence suggests that the separation of the two centrioles (disengagement) is required for centrosome duplication. After centriole disengagement, a proteinaceous linker is established that still connects the two centrioles. In G2, this linker is resolved (centrosome separation), thereby allowing the centrosomes to separate and form the poles of the bipolar spindle. Recent work has identified new players that regulate these two processes and revealed unexpected mechanisms controlling the centrosome cycle.

Sign in / Sign up

Export Citation Format

Share Document