scholarly journals Cdc42 GTPase regulates ESCRTs in nuclear envelope sealing and ER remodeling

2020 ◽  
Vol 219 (8) ◽  
Author(s):  
Michelle Seiko Lu ◽  
David G. Drubin
Keyword(s):  
Cell Migration ◽  
Genetic Analysis ◽  
Nuclear Envelope ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Molecular Switches ◽  
Small Gtpases ◽  
Cytoskeletal Remodeling ◽  
Cell Divisions ◽  
Rho Family

Small GTPases of the Rho family are binary molecular switches that regulate a variety of processes including cell migration and oriented cell divisions. Known Cdc42 effectors include proteins involved in cytoskeletal remodeling and kinase-dependent transcription induction, but none are involved in the maintenance of nuclear envelope integrity or ER morphology. Maintenance of nuclear envelope integrity requires the EndoSomal Complexes Required for Transport (ESCRT) proteins, but how they are regulated in this process remains unknown. Here, we show by live-cell imaging a novel Cdc42 localization with ESCRT proteins at sites of nuclear envelope and ER fission and, by genetic analysis of cdc42 mutant yeast, uncover a unique Cdc42 function in regulation of ESCRT proteins at the nuclear envelope and sites of ER tubule fission. Our findings implicate Cdc42 in nuclear envelope sealing and ER remodeling, where it regulates ESCRT disassembly to maintain nuclear envelope integrity and proper ER architecture.

scholarly journals Cdc42 GTPase regulates ESCRTs in nuclear envelope sealing and ER remodeling

2019 ◽  
Author(s):  
Michelle S. Lu ◽  
David G. Drubin
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Live Cell Imaging ◽  
Rho Gtpase ◽  
Molecular Switches ◽  
Cell Types ◽  
Eukaryotic Cell ◽  
Small Gtpases ◽  
Cytoskeletal Remodeling ◽  
Rho Family

AbstractSmall GTPases of the Rho family are binary molecular switches that regulate a variety of processes including cell migration and oriented cell divisions. Known Cdc42 effectors include proteins involved in cytoskeletal remodeling and kinase-dependent transcription induction, but none involved in the maintenance of nuclear envelope integrity or endoplasmic reticulum (ER) morphology. Maintenance of nuclear envelope integrity requires the EndoSomal Complexes Required for Transport (ESCRT) proteins, but how they are regulated in this process remains unknown. Here we show by live-cell imaging a novel Cdc42 localization with ESCRT proteins at sites of nuclear envelope and ER fission, and by genetic analysis, uncover a unique Cdc42 function in regulation of ESCRT proteins at the nuclear envelope and sites of ER tubule fission. Our findings implicate Cdc42 in nuclear envelope sealing and ER remodeling, where it regulates ESCRT disassembly to maintain nuclear envelope integrity and proper ER architecture.SummaryThe small Rho GTPase Cdc42 is a well-known regulator of cytoskeletal rearrangement and polarity development in all eukaryotic cell types. Here, Lu and Drubin report the serendipitous discovery of a novel Cdc42-ESCRT-nuclear envelope/endoplasmic reticulum connection.

scholarly journals Integrins traffic rapidly via circular dorsal ruffles and macropinocytosis during stimulated cell migration

2011 ◽  
Vol 193 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Zhizhan Gu ◽  
Erika H. Noss ◽  
Victor W. Hsu ◽  
Michael B. Brenner
Keyword(s):  
Functional Analysis ◽  
Cell Migration ◽  
Growth Factor ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Focal Adhesions ◽  
Initial Step ◽  
Ventral Surface ◽  
Platelet Derived Growth Factor ◽  
Trailing Edges

During cell migration, integrins are redistributed from focal adhesions undergoing disassembly at the cell’s trailing edges to new focal adhesions assembling at leading edges. The initial step of integrin redistribution is thought to require clathrin-mediated endocytosis. However, whether clathrin-mediated endocytosis functions in different contexts, such as basal versus stimulated migration, has not been determined. In this paper, we examine the spatial and temporal redistribution of integrins from focal adhesions upon stimulation by growth factors. Four-dimensional confocal live-cell imaging along with functional analysis reveals that surface integrins do not undergo significant endocytosis at ventral focal adhesions upon cell stimulation with the platelet-derived growth factor. Rather, they abruptly redistribute to dorsal circular ruffles, where they are internalized through macropinocytosis. The internalized integrins then transit through recycling endosomal compartments to repopulate newly formed focal adhesions on the ventral surface. These findings explain why integrins have long been observed to redistribute through both surface-based and internal routes and identify a new function for macropinocytosis during growth factor–induced cell migration.

Live cell imaging analysis of the epigenetic regulation of the human endothelial cell migration at single-cell resolution

Lab on a Chip ◽  
2012 ◽  
Vol 12 (17) ◽  
pp. 3063 ◽  
Author(s):  
Chunhong Zheng ◽  
Zhilong Yu ◽  
Ying Zhou ◽  
Louis Tao ◽  
Yuhong Pang ◽  
...  
Keyword(s):  
Cell Migration ◽  
Endothelial Cell ◽  
Single Cell ◽  
Epigenetic Regulation ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Endothelial Cell Migration ◽  
Human Endothelial Cell ◽  
Imaging Analysis

scholarly journals Rho Family of Ras-Like GTPases in Early-Branching Animals

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2279
Author(s):  
Silvestar Beljan ◽  
Maja Herak Bosnar ◽  
Helena Ćetković
Keyword(s):  
Current Knowledge ◽  
Molecular Switches ◽  
Cellular Responses ◽  
Small Gtpases ◽  
Rho Family Gtpases ◽  
History Of ◽  
Rho Family ◽  
Major Branch ◽  
External Signals ◽  
Insight Into

Non-bilaterian animals consist of four phyla; Porifera, Cnidaria, Ctenophora, and Placozoa. These early-diverging animals are crucial for understanding the evolution of the entire animal lineage. The Rho family of proteins make up a major branch of the Ras superfamily of small GTPases, which function as key molecular switches that play important roles in converting and amplifying external signals into cellular responses. This review represents a compilation of the current knowledge on Rho-family GTPases in non-bilaterian animals, the available experimental data about their biochemical characteristics and functions, as well as original bioinformatics analysis, in order to gain a general insight into the evolutionary history of Rho-family GTPases in simple animals.

scholarly journals Nucleoplasmic Lamin C Rapidly Accumulates at Sites of Nuclear Envelope Rupture with BAF and cGAS

2022 ◽  
Author(s):  
Yohei Kono ◽  
Stephen A. Adam ◽  
Karen Reddy ◽  
Yixian Zheng ◽  
Ohad Medalia ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Nuclear Lamina ◽  
Structural Components ◽  
Cell Nuclei ◽  
Embryonic Fibroblasts ◽  
Nuclear Lamins ◽  
Laser Microirradiation

In mammalian cell nuclei, the nuclear lamina (NL) underlies the nuclear envelope (NE) to maintain nuclear structure. The nuclear lamins, the major structural components of the NL, are involved in the protection against NE rupture induced by mechanical stress. However, the specific role of the lamins in repair of NE ruptures has not been fully determined. Our analyses using immunofluorescence and live-cell imaging revealed that lamin C but not the other lamin isoforms rapidly accumulated at sites of NE rupture induced by laser microirradiation in mouse embryonic fibroblasts. The immunoglobulin-like fold domain and the NLS were required for the recruitment from the nucleoplasm to the rupture sites with the Barrier-to-autointegration factor (BAF). The accumulation of nuclear BAF and cytoplasmic cyclic GMP-AMP (cGAMP) synthase (cGAS) at the rupture sites was in part dependent on lamin A/C. These results suggest that nucleoplasmic lamin C, BAF and cGAS concertedly accumulate at sites of NE rupture for repair.

scholarly journals Rear-polarized Wnt5a-receptor-actin-myosin-polarity (WRAMP) structures promote the speed and persistence of directional cell migration

2017 ◽  
Vol 28 (14) ◽  
pp. 1924-1936 ◽  
Author(s):  
Mary Katherine Connacher ◽  
Jian Wei Tay ◽  
Natalie G. Ahn
Keyword(s):  
Cell Migration ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Cell Movement ◽  
Leading Edge ◽  
Cellular Mechanism ◽  
Directional Movement ◽  
New Directions ◽  
And Function ◽  
Directional Cell Migration

In contrast to events at the cell leading edge, rear-polarized mechanisms that control directional cell migration are poorly defined. Previous work described a new intracellular complex, the Wnt5a-receptor-actomyosin polarity (WRAMP) structure, which coordinates the polarized localization of MCAM, actin, and myosin IIB in a Wnt5a-induced manner. However, the polarity and function for the WRAMP structure during cell movement were not determined. Here we characterize WRAMP structures during extended cell migration using live-cell imaging. The results demonstrate that cells undergoing prolonged migration show WRAMP structures stably polarized at the rear, where they are strongly associated with enhanced speed and persistence of directional movement. Strikingly, WRAMP structures form transiently, with cells displaying directional persistence during periods when they are present and cells changing directions randomly when they are absent. Cells appear to pause locomotion when WRAMP structures disassemble and then migrate in new directions after reassembly at a different location, which forms the new rear. We conclude that WRAMP structures represent a rear-directed cellular mechanism to control directional migration and that their ability to form dynamically within cells may control changes in direction during extended migration.

scholarly journals The kinesin KIF1C transports APC-dependent mRNAs to cell protrusions

2020 ◽  
Author(s):  
Xavier Pichon ◽  
Konstadinos Moissoglu ◽  
Emeline Coleno ◽  
Tianhong Wang ◽  
Arthur Imbert ◽  
...  
Keyword(s):  
Cell Migration ◽  
Mammalian Cells ◽  
Live Cell Imaging ◽  
Feedback Loop ◽  
Cell Imaging ◽  
Rna Localization ◽  
Dependent Manner ◽  
Rna Transport ◽  
Cellular Functions ◽  
Transport Pathway

AbstractRNA localization and local translation are important for numerous cellular functions. In mammals, a class of mRNAs localize to cytoplasmic protrusions in an APC-dependent manner, with roles during cell migration. Here, we investigated this localization mechanism. We found that the KIF1C motor interacts with APC-dependent mRNAs and is required for their localization. Live cell imaging revealed rapid, active transport of single mRNAs over long distances that requires both microtubules and KIF1C. Two color imaging directly showed single mRNAs transported by single KIF1C motors, with the 3’UTR being sufficient to trigger KIF1C-dependent RNA transport and localization. Moreover, KIF1C remained associated with peripheral, multimeric RNA clusters and was required for their formation. These results reveal an RNA transport pathway in mammalian cells, in which the KIF1C motor has a dual role both in transporting RNAs and in promoting their clustering within cytoplasmic protrusions. Interestingly, KIF1C also transports its own mRNA suggesting a possible feedback loop acting at the level of mRNA transport.

scholarly journals Automated live cell imaging of cell migration across a microfluidic-controlled chemoattractant gradient

2015 ◽  
Vol 12 (11) ◽  
pp. vii-viii ◽  
Author(s):  
Philip Lee ◽  
Cindy S Y Chen ◽  
Terry Gaige ◽  
Paul J Hung
Keyword(s):  
Cell Migration ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell

scholarly journals GMFβ controls branched actin content and lamellipodial retraction in fibroblasts

2015 ◽  
Vol 209 (6) ◽  
pp. 803-812 ◽  
Author(s):  
Elizabeth M. Haynes ◽  
Sreeja B. Asokan ◽  
Samantha J. King ◽  
Heath E. Johnson ◽  
Jason M. Haugh ◽  
...  
Keyword(s):  
Cell Migration ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Directional Migration ◽  
Pharmacological Inhibition ◽  
Primary Activity ◽  
And Migration ◽  
Important Structure

The lamellipodium is an important structure for cell migration containing branched actin nucleated via the Arp2/3 complex. The formation of branched actin is relatively well studied, but less is known about its disassembly and how this influences migration. GMF is implicated in both Arp2/3 debranching and inhibition of Arp2/3 activation. Modulation of GMFβ, a ubiquitous GMF isoform, by depletion or overexpression resulted in changes in lamellipodial dynamics, branched actin content, and migration. Acute pharmacological inhibition of Arp2/3 by CK-666, coupled to quantitative live-cell imaging of the complex, showed that depletion of GMFβ decreased the rate of branched actin disassembly. These data, along with mutagenesis studies, suggest that debranching (not inhibition of Arp2/3 activation) is a primary activity of GMFβ in vivo. Furthermore, depletion or overexpression of GMFβ disrupted the ability of cells to directionally migrate to a gradient of fibronectin (haptotaxis). These data suggest that debranching by GMFβ plays an important role in branched actin regulation, lamellipodial dynamics, and directional migration.

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