scholarly journals LIM kinase1 regulates mitotic centrosome integrity via its activity on dynein light intermediate chains

Open Biology ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 170202 ◽  
Author(s):  
Sirong Ou ◽  
Mei-Hua Tan ◽  
Ting Weng ◽  
HoiYeung Li ◽  
Cheng-Gee Koh
Keyword(s):  
Protein Transport ◽  
Protein Localization ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Centrosomal Protein ◽  
And Function ◽  
Cytoskeleton Dynamics ◽  
Dynein Light Intermediate Chains ◽  
Intermediate Chains ◽  
Mitotic Spindle Pole

Abnormal centrosome number and function have been implicated in tumour development. LIM kinase1 (LIMK1), a regulator of actin cytoskeleton dynamics, is found to localize at the mitotic centrosome. However, its role at the centrosome is not fully explored. Here, we report that LIMK1 depletion resulted in multi-polar spindles and defocusing of centrosomes, implicating its involvement in the regulation of mitotic centrosome integrity. LIMK1 could influence centrosome integrity by modulating centrosomal protein localization at the spindle pole. Interestingly, dynein light intermediate chains (LICs) are able to rescue the defects observed in LIMK1-depleted cells. We found that LICs are potential novel interacting partners and substrates of LIMK1 and that LIMK1 phosphorylation regulates cytoplasmic dynein function in centrosomal protein transport, which in turn impacts mitotic spindle pole integrity.

scholarly journals Distinct roles for dynein light intermediate chains in neurogenesis, migration, and terminal somal translocation

2019 ◽  
Vol 218 (3) ◽  
pp. 808-819 ◽  
Author(s):  
João Carlos Gonçalves ◽  
Tiago J. Dantas ◽  
Richard B. Vallee
Keyword(s):  
Neuronal Migration ◽  
Cytoplasmic Dynein ◽  
Neural Progenitors ◽  
In Utero Electroporation ◽  
Neocortical Development ◽  
Newborn Neurons ◽  
Dynein Light Intermediate Chains ◽  
Intermediate Chains ◽  
Developing Rat ◽  
Insight Into

Cytoplasmic dynein participates in multiple aspects of neocortical development. These include neural progenitor proliferation, morphogenesis, and neuronal migration. The cytoplasmic dynein light intermediate chains (LICs) 1 and 2 are cargo-binding subunits, though their relative roles are not well understood. Here, we used in utero electroporation of shRNAs or LIC functional domains to determine the relative contributions of the two LICs in the developing rat brain. We find that LIC1, through BicD2, is required for apical nuclear migration in neural progenitors. In newborn neurons, we observe specific roles for LIC1 in the multipolar to bipolar transition and glial-guided neuronal migration. In contrast, LIC2 contributes to a novel dynein role in the little-studied mode of migration, terminal somal translocation. Together, our results provide novel insight into the LICs’ unique functions during brain development and dynein regulation overall.

scholarly journals Dynein light intermediate chains maintain spindle bipolarity by functioning in centriole cohesion

2014 ◽  
Vol 207 (4) ◽  
pp. 499-516 ◽  
Author(s):  
Laura A. Jones ◽  
Cécile Villemant ◽  
Toby Starborg ◽  
Anna Salter ◽  
Georgina Goddard ◽  
...  
Keyword(s):  
Cell Division ◽  
Cytoplasmic Dynein ◽  
Small Interfering Rnas ◽  
Cellular Functions ◽  
Multipolar Spindles ◽  
Early Embryos ◽  
Microtubule Motor ◽  
Morpholino Oligonucleotides ◽  
Dynein Light Intermediate Chains ◽  
Intermediate Chains

Cytoplasmic dynein 1 (dynein) is a minus end–directed microtubule motor protein with many cellular functions, including during cell division. The role of the light intermediate chains (LICs; DYNC1LI1 and 2) within the complex is poorly understood. In this paper, we have used small interfering RNAs or morpholino oligonucleotides to deplete the LICs in human cell lines and Xenopus laevis early embryos to dissect the LICs’ role in cell division. We show that although dynein lacking LICs drives microtubule gliding at normal rates, the LICs are required for the formation and maintenance of a bipolar spindle. Multipolar spindles with poles that contain single centrioles were formed in cells lacking LICs, indicating that they are needed for maintaining centrosome integrity. The formation of multipolar spindles via centrosome splitting after LIC depletion could be rescued by inhibiting Eg5. This suggests a novel role for the dynein complex, counteracted by Eg5, in the maintenance of centriole cohesion during mitosis.

scholarly journals Recruitment of dynein to late endosomes and lysosomes through light intermediate chains

2011 ◽  
Vol 22 (4) ◽  
pp. 467-477 ◽  
Author(s):  
Serena C. Tan ◽  
Julian Scherer ◽  
Richard B. Vallee
Keyword(s):  
Full Range ◽  
Cytoplasmic Dynein ◽  
Endocytic Pathway ◽  
Cellular Processes ◽  
Late Endosomes ◽  
Wide Range ◽  
Range Of Functions ◽  
Specific Association ◽  
Dynein Light Intermediate Chains ◽  
Intermediate Chains

Cytoplasmic dynein is involved in a wide range of cellular processes, but how it is regulated and how it recognizes an extremely wide range of cargo are incompletely understood. The dynein light intermediate chains, LIC1 and LIC2 (DYNC1LI1 and DYNC1LI2, respectively), have been implicated in cargo binding, but their full range of functions is unknown. Using LIC isoform-specific antibodies, we report the first characterization of their subcellular distribution and identify a specific association with elements of the late endocytic pathway, but not other vesicular compartments. LIC1 and LIC2 RNA interference (RNAi) each specifically disrupts the distribution of lysosomes and late endosomes. Stimulation of dynein-mediated late-endosomal transport by the Rab7-interacting lysosomal protein (RILP) is reversed by LIC1 RNAi, which displaces dynein, but not dynactin, from these structures. Conversely, expression of ΔN-RILP or the dynactin subunit dynamitin each fails to displace dynein, but not dynactin. Thus, using a variety of complementary approaches, our results indicate a novel specific role for the LICs in dynein recruitment to components of the late endocytic pathway.

scholarly journals Functional Coordination of Three Mitotic Motors inDrosophila Embryos

2000 ◽  
Vol 11 (1) ◽  
pp. 241-253 ◽  
Author(s):  
David J. Sharp ◽  
Heather M. Brown ◽  
Mijung Kwon ◽  
Gregory C. Rogers ◽  
Gina Holland ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Nuclear Envelope Breakdown ◽  
Mitotic Motors ◽  
Balance Of Forces ◽  
Spindle Elongation ◽  
And Function ◽  
Anaphase B ◽  
Drosophila Embryos

It is well established that multiple microtubule-based motors contribute to the formation and function of the mitotic spindle, but how the activities of these motors interrelate remains unclear. Here we visualize spindle formation in living Drosophila embryos to show that spindle pole movements are directed by a temporally coordinated balance of forces generated by three mitotic motors, cytoplasmic dynein, KLP61F, and Ncd. Specifically, our findings suggest that dynein acts to move the poles apart throughout mitosis and that this activity is augmented by KLP61F after the fenestration of the nuclear envelope, a process analogous to nuclear envelope breakdown, which occurs at the onset of prometaphase. Conversely, we find that Ncd generates forces that pull the poles together between interphase and metaphase, antagonizing the activity of both dynein and KLP61F and serving as a brake for spindle assembly. During anaphase, however, Ncd appears to have no effect on spindle pole movements, suggesting that its activity is down-regulated at this time, allowing dynein and KLP61F to drive spindle elongation during anaphase B.

scholarly journals Nudel Modulates Kinetochore Association and Function of Cytoplasmic Dynein in M Phase

2007 ◽  
Vol 18 (7) ◽  
pp. 2656-2666 ◽  
Author(s):  
Yun Liang ◽  
Wei Yu ◽  
Yan Li ◽  
Lihou Yu ◽  
Qiangge Zhang ◽  
...  
Keyword(s):  
Protein Transport ◽  
Cytoplasmic Dynein ◽  
Mitotic Progression ◽  
Kinetochore Protein ◽  
Nuclear Envelope Breakdown ◽  
Spindle Poles ◽  
M Phase ◽  
And Function ◽  
Force Generator

The microtubule-based motor cytoplasmic dynein/dynactin is a force generator at the kinetochore. It also transports proteins away from kinetochores to spindle poles. Regulation of such diverse functions, however, is poorly understood. We have previously shown that Nudel is critical for dynein-mediated protein transport, whereas mitosin, a kinetochore protein that binds Nudel, is involved in retention of kinetochore dynein/dynactin against microtubule-dependent stripping. Here we demonstrate that Nudel is required for robust localization of dynein/dynactin at the kinetochore. It localizes to kinetochores after nuclear envelope breakdown, depending mostly (∼78%) on mitosin and slightly on dynein/dynactin. Depletion of Nudel by RNA interference (RNAi) or overexpression of its mutant incapable of binding either Lis1 or dynein heavy chain abolishes the kinetochore protein transport and mitotic progression. Similar to mitosin RNAi, Nudel RNAi also leads to increased stripping of kinetochore dynein/dynactin in the presence of microtubules. Taking together, our results suggest a dual role of kinetochore Nudel: it activates dynein-mediated protein transport and, when interacting with both mitosin and dynein, stabilizes kinetochore dynein/dynactin against microtubule-dependent stripping to facilitate the force generation function of the motor.

Spatial control of actin-based motility through plasmalemmal PtdIns(4,5)P2-rich raft assemblies.

2005 ◽  
Vol 72 ◽  
pp. 119-127 ◽  
Author(s):  
Tamara Golub ◽  
Caroni Pico
Keyword(s):  
Protein Kinase ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Lipid Rafts ◽  
Patch Clustering ◽  
Pkc Protein Kinase C ◽  
Membrane Bound ◽  
And Function ◽  
Cytoskeleton Dynamics ◽  
Syndrome Protein

The interactions of cells with their environment involve regulated actin-based motility at defined positions along the cell surface. Sphingolipid- and cholesterol-dependent microdomains (rafts) order proteins at biological membranes, and have been implicated in most signalling processes at the cell surface. Many membrane-bound components that regulate actin cytoskeleton dynamics and cell-surface motility associate with PtdIns(4,5)P2-rich lipid rafts. Although raft integrity is not required for substrate-directed cell spreading, or to initiate signalling for motility, it is a prerequisite for sustained and organized motility. Plasmalemmal rafts redistribute rapidly in response to signals, triggering motility. This process involves the removal of rafts from sites that are not interacting with the substrate, apparently through endocytosis, and a local accumulation at sites of integrin-mediated substrate interactions. PtdIns(4,5)P2-rich lipid rafts can assemble into patches in a process depending on PtdIns(4,5)P2, Cdc42 (cell-division control 42), N-WASP (neural Wiskott-Aldrich syndrome protein) and actin cytoskeleton dynamics. The raft patches are sites of signal-induced actin assembly, and their accumulation locally promotes sustained motility. The patches capture microtubules, which promote patch clustering through PKA (protein kinase A), to steer motility. Raft accumulation at the cell surface, and its coupling to motility are influenced greatly by the expression of intrinsic raft-associated components that associate with the cytosolic leaflet of lipid rafts. Among them, GAP43 (growth-associated protein 43)-like proteins interact with PtdIns(4,5)P2 in a Ca2+/calmodulin and PKC (protein kinase C)-regulated manner, and function as intrinsic determinants of motility and anatomical plasticity. Plasmalemmal PtdIns(4,5)P2-rich raft assemblies thus provide powerful organizational principles for tight spatial and temporal control of signalling in motility.

Gene Overexpression as a Tool for Identifying New trans-Acting Factors Involved in Translation Termination in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 585-594
Author(s):  
Olivier Namy ◽  
Isabelle Hatin ◽  
Guillaume Stahl ◽  
Hongmei Liu ◽  
Stephanie Barnay ◽  
...  
Keyword(s):  
Protein Transport ◽  
Stop Codon ◽  
Translation Termination ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Release Factor ◽  
Lacz Reporter Gene ◽  
Pole Body ◽  
Secondary Phenotypes ◽  
Termination Process

Abstract In eukaryotes, translation termination is dependent on the availability of both release factors, eRF1 and eRF3; however, the precise mechanisms involved remain poorly understood. In particular, the fact that the phenotype of release factor mutants is pleiotropic could imply that other factors and interactions are involved in translation termination. To identify unknown elements involved in this process, we performed a genetic screen using a reporter strain in which a leaky stop codon is inserted in the lacZ reporter gene, attempting to isolate factors modifying termination efficiency when overexpressed. Twelve suppressors and 11 antisuppressors, increasing or decreasing termination readthrough, respectively, were identified and analyzed for three secondary phenotypes often associated with translation mutations: thermosensitivity, G418 sensitivity, and sensitivity to osmotic pressure. Interestingly, among these candidates, we identified two genes, SSO1 and STU2, involved in protein transport and spindle pole body formation, respectively, suggesting puzzling connections with the translation termination process.

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