A Dynamin–Cortactin–Arp2/3 Complex Mediates Actin Reorganization in Growth Factor-stimulated Cells

Krueger, Eugene W.; Orth, James D.; Cao, Hong; McNiven, Mark A.

doi:10.1091/mbc.e02-08-0466

Cited by 199 publications

(251 citation statements)

References 43 publications

Supporting

Mentioning

234

Contrasting

Order By: Relevance

“…These data suggest that dynamin function in macropinocytosis might be related to its role in actin regulation and distinct from its role in CME. Indeed, as has been reported (Krueger et al, 2003), Dyn2-GFP localizes to dorsal ruffles upon PDGF stimulation in punctate structures that do not colocalize with the clathrincoated pits (Supplemental Figure S5). …”

Section: Dyn2 Is Required For Pdgf-stimulated Macropinocytosis But Nsupporting

confidence: 70%

Isoform and Splice-Variant Specific Functions of Dynamin-2 Revealed by Analysis of Conditional Knock-Out Cells

Liu

Surka

Schroeter

et al. 2008

MBoC

125

163

View full text Add to dashboard Cite

Dynamin (Dyn) is a multifunctional GTPase implicated in several cellular events, including endocytosis, intracellular trafficking, cell signaling, and cytokinesis. The mammalian genome encodes three isoforms, Dyn1, Dyn2, and Dyn3, and several splice variants of each, leading to the suggestion that distinct isoforms and/or distinct splice variants might mediate distinct cellular functions. We generated a conditional Dyn2 KO cell line and performed knockout and reconstitution experiments to explore the isoform-and splice variant specific cellular functions of ubiquitously expressed Dyn2. We find that Dyn2 is required for clathrin-mediated endocytosis (CME), p75 export from the Golgi, and PDGFstimulated macropinocytosis and cytokinesis, but not for other endocytic pathways. Surprisingly, CME and p75 exocytosis were efficiently rescued by reintroduction of Dyn2, but not Dyn1, suggesting that these two isoforms function differentially in vesicular trafficking in nonneuronal cells. Both isoforms rescued macropinocytosis and cytokinesis, suggesting that dynamin function in these processes might be mechanistically distinct from its role in CME. Although all four Dyn2 splice variants could equally restore CME, Dyn2ba and -bb were more effective at restoring p75 exocytosis. This splice variant specificity correlated with their differential targeting to the Golgi. These studies reveal isoform and splice-variant specific functions for Dyn2. INTRODUCTIONDynamin (Dyn) is an ϳ100-kDa multidomain GTPase that was first identified as a microtubule binding and bundling protein (Shpetner and Vallee, 1989). Subsequently, dynamin was found to be the mammalian homologue of the Drosophila protein shibire, mutations in which block endocytosis, including synaptic vesicle recycling (Chen et al., 1991;van der Bliek and Meyerowitz, 1991). Dynamin is conserved throughout higher eukaryotes. There is a single gene in Drosophila and Caenorhabditis elegans, but there are three dynamin isoforms in mammals: Dyn1, which is specifically expressed in neurons; Dyn2, which is ubiquitously expressed; and Dyn3, which is mainly expressed in the brain and testes (Urrutia et al., 1997, Ferguson et al., 2007.The best-studied cellular function of dynamin is its involvement in clathrin-mediated endocytosis (CME; Hinshaw, 2000;Sever et al., 2000;Praefcke and McMahon, 2004). However, dynamin has also been implicated in several other membrane-trafficking events including both caveolae-mediated and clathrin-and caveolin-independent endocytic pathways Oh et al., 1998;Lamaze et al., 2001;Pelkmans et al., 2002), phagocytosis (Gold et al., 1999;Yu et al., 2006), macropinocytosis (Schlunck et al., 2004), and trafficking from the trans-Golgi network (TGN; Jones et al., 1998;Kreitzer et al., 2000;Bonazzi et al., 2005). Because these functions have mostly emerged from studying the effects of overexpression of dominant-negative dynamin mutants, they may reflect indirect or nonspecific effects. Moreover, it is not known whether different dynamin isoforms and/or splice varia...

show abstract

Section: Dyn2 Is Required For Pdgf-stimulated Macropinocytosis But Nsupporting

confidence: 70%

Isoform and Splice-Variant Specific Functions of Dynamin-2 Revealed by Analysis of Conditional Knock-Out Cells

Liu

Surka

Schroeter

et al. 2008

MBoC

125

163

View full text Add to dashboard Cite

show abstract

“…Rigid actin stress fibers are disassembled upon dorsal circular ruffle (DCR) formation leaving a fine cortical actin meshwork behind, from which cell membrane protrusions like lamellipodia can emerge [150,151]. DCRs are shortlived actin structures formed at the dorsal surface of growth factor (PDGF, HGF, EGF)-stimulated cells.…”

Section: Membrane Rufflesmentioning

confidence: 99%

EMT, the cytoskeleton, and cancer cell invasion

Yilmaz

Christofori

2009

Cancer Metastasis Rev

1,548

1,314

View full text Add to dashboard Cite

The metastatic process, i.e. the dissemination of cancer cells throughout the body to seed secondary tumors at distant sites, requires cancer cells to leave the primary tumor and to acquire migratory and invasive capabilities. In a process of epithelial-mesenchymal transition (EMT), besides changing their adhesive repertoire, cancer cells employ developmental processes to gain migratory and invasive properties that involve a dramatic reorganization of the actin cytoskeleton and the concomitant formation of membrane protrusions required for invasive growth. The molecular processes underlying such cellular changes are still only poorly understood, and the various migratory organelles, including lamellipodia, filopodia, invadopodia and podosomes, still require a better functional and molecular characterization. Notably, direct experimental evidence linking the formation of migratory membrane protrusions and the process of EMT and tumor metastasis is still lacking. In this review, we have summarized recent novel insights into the molecular processes and players underlying EMT on one side and the formation of invasive membrane protrusions on the other side.

show abstract

“…DYN-1 is the nematode homologue of mammalian dynamin, and belongs to a family of large GTPases that have been linked to both organization of the actin cytoskeleton 55 Ã 58 and internalization of antibody-opsonized cells 59 . Dynamin has also been shown to play a role in receptormediated endocytosis and protein trafficking 60 and to form an endogenous complex with Arp2/3 and other actin binding proteins 55 . However, the exact function of dynamin during remodeling of the actin cytoskeleton in the context of engulfment is unclear 60 .…”

Section: An Unbiased Genetic Screen Identifies Additional Genes Requimentioning

confidence: 99%

A pathway for phagosome maturation during engulfment of apoptotic cells

et al. 2008

View full text Add to dashboard Cite

The efficient removal of apoptotic cells is critical for the physiological well-being of the organism 1 Ã 4 ; defects in corpse removal have been linked to autoimmune disease 4,5 . While several players regulating the early steps of corpse recognition and internalization have been characterized 6 , the molecules and mechanisms relevant to the subsequent processing of the internalized corpses are poorly understood. Here, we identify a novel pathway for the processing of internalized apoptotic cells in C. elegans and in mammals. First, we show that RAB-5 and RAB-7 are sequentially recruited to phagosomes containing apoptotic corpses as they mature within phagocytes, and that both proteins are required for efficient corpse clearance. We then used targeted genetic screens to identify players regulating the recruitment and/or retention of Rab5 and Rab7 to phagosomes. Seven members of the HOPS complex (a Rab7 activator/effector complex) were required for Rab7 localization or retention on phagosomes. In an effort to identify factors that regulate Rab5 recruitment, we undertook an unbiased reverse genetic screen and identified 61 genes potentially required for corpse removal. In-depth analysis of two candidate genes, vps-34 and dyn-1/ dynamin, showed accumulation of internalized, but undegraded corpses within abnormal phagosomes that are defective in RAB-5 recruitment. Using a series of genetic and biochemical experiments in worms and mammalian cells, we ordered these proteins in a pathway, with DYN-1 functioning upstream of VPS-34, in the recruitment/retention of Rab5 to the nascent phagosome. Further, we identified a novel biochemical complex containing Vps34, dynamin and Rab5 GDP , providing a mechanism for Rab5 recruitment to the nascent phagosome.Removal of apoptotic cells (engulfment) is an essential process that occurs throughout life in multi-cellular animals as part of development, homeostasis, and wound healing1Ã4 , 7 , 8. Engulfment) can be broken down into a series of steps, comprising recognition, internalization, phagosome maturation and finally lysosomal degradation of the apoptotic cell by the phagocyte. In mammals, impaired clearance of apoptotic cell corpses can lead to exposure of autoantigens, resulting in onset of autoimmune diseases, such as systemic lupus erythematosus 4,9,10 . Modulation of the engulfment process is therefore a potential therapeutic target in these conditions. One of the fundamental challenges in understanding how defects in engulfment of apoptotic cells translates into diseased states is the identification of critical players involved in corpse removal and how these proteins orchestrate the different stages of engulfment.The nematode C. elegans represents a powerful genetic tool for the study of programmed cell death 11,12 . Large numbers of cells are induced to die during two periods in the life of a worm: during embryonic and larval morphogenesis and during germ cell development 13 . Genetic studies have identified two evolutionarily conserved signaling pathways invol...

show abstract

A Dynamin–Cortactin–Arp2/3 Complex Mediates Actin Reorganization in Growth Factor-stimulated Cells

Cited by 199 publications

References 43 publications

Isoform and Splice-Variant Specific Functions of Dynamin-2 Revealed by Analysis of Conditional Knock-Out Cells

Isoform and Splice-Variant Specific Functions of Dynamin-2 Revealed by Analysis of Conditional Knock-Out Cells

EMT, the cytoskeleton, and cancer cell invasion

A pathway for phagosome maturation during engulfment of apoptotic cells

Contact Info

Product

Resources

About