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Youn YJ, Lee J. Chronic venous insufficiency and varicose veins of the lower extremities. Korean J Intern Med 2019; 34:269-283. [PMID: 30360023 PMCID: PMC6406103 DOI: 10.3904/kjim.2018.230] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/08/2018] [Indexed: 12/15/2022] Open
Abstract
Chronic venous insufficiency (CVI) of the lower extremities manifests itself in various clinical spectrums, ranging from asymptomatic but cosmetic problems to severe symptoms, such as venous ulcer. CVI is a relatively common medical problem but is often overlooked by healthcare providers because of an underappreciation of the magnitude and impact of the problem, as well as incomplete recognition of the various presenting manifestations of primary and secondary venous disorders. The prevalence of CVI in South Korea is expected to increase, given the possible underdiagnoses of CVI, the increase in obesity and an aging population. This article reviews the pathophysiology of CVI of the lower extremities and highlights the role of duplex ultrasound in its diagnosis and radiofrequency ablation, and iliac vein stenting in its management.
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Affiliation(s)
- Young Jin Youn
- Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
- Division of Interventional Cardiology, Calhoun Cardiology Center, UConn Health, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Juyong Lee
- Division of Interventional Cardiology, Calhoun Cardiology Center, UConn Health, University of Connecticut School of Medicine, Farmington, CT, USA
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Sokolova OS, Chemeris A, Guo S, Alioto SL, Gandhi M, Padrick S, Pechnikova E, David V, Gautreau A, Goode BL. Structural Basis of Arp2/3 Complex Inhibition by GMF, Coronin, and Arpin. J Mol Biol 2016; 429:237-248. [PMID: 27939292 DOI: 10.1016/j.jmb.2016.11.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/23/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
The evolutionarily conserved Arp2/3 complex plays a central role in nucleating the branched actin filament arrays that drive cell migration, endocytosis, and other processes. To better understand Arp2/3 complex regulation, we used single-particle electron microscopy to compare the structures of Arp2/3 complex bound to three different inhibitory ligands: glia maturation factor (GMF), Coronin, and Arpin. Although the three inhibitors have distinct binding sites on Arp2/3 complex, they each induced an "open" nucleation-inactive conformation. Coronin promoted a standard (previously described) open conformation of Arp2/3 complex, with the N-terminal β-propeller domain of Coronin positioned near the p35/ARPC2 subunit of Arp2/3 complex. GMF induced two distinct open conformations of Arp2/3 complex, which correlated with the two suggested binding sites for GMF. Furthermore, GMF synergized with Coronin in inhibiting actin nucleation by Arp2/3 complex. Arpin, which uses VCA-related acidic (A) motifs to interact with the Arp2/3 complex, induced the standard open conformation, and two new masses appeared at positions near Arp2 and Arp3. Furthermore, Arpin showed additive inhibitory effects on Arp2/3 complex with Coronin and GMF. Together, these data suggest that Arp2/3 complex conformation is highly polymorphic and that its activities can be controlled combinatorially by different inhibitory ligands.
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Affiliation(s)
- Olga S Sokolova
- Department of Biology, Moscow M.V. Lomonosov University, Moscow 119234, Russia
| | - Angelina Chemeris
- Department of Biology, Moscow M.V. Lomonosov University, Moscow 119234, Russia; Ecole Polytechnique, CNRS UMR7654, Palaiseau 91120, France
| | - Siyang Guo
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | | | - Meghal Gandhi
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - Shae Padrick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | | | - Violaine David
- Ecole Polytechnique, CNRS UMR7654, Palaiseau 91120, France
| | | | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA 02453, USA.
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Wsp1, a GBD/CRIB domain-containing WASP homolog, is required for growth, morphogenesis, and virulence of Cryptococcus neoformans. EUKARYOTIC CELL 2011; 10:521-9. [PMID: 21357479 DOI: 10.1128/ec.00274-10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human endocytic protein ITSN1 regulates actin reorganization by activating Rho family GTPases, such as Cdc42. The process is enhanced by ITSN binding of WASP, an effector of Cdc42 and a potent activator of actin polymerization. In the human pathogen Cryptococcus neoformans, endocytic protein Cin1 also interacts with Cdc42 and Wsp1, an uncharacterized WASP homolog, but the significance of these interactions remains unknown. Wsp1 contains several conserved domains, including a WASP homology 1 domain (WH1), a GTPase binding/Cdc42 and Rac interactive binding domain (GBD/CRIB), and a C-terminal domain composed of verprolin-like, central, and acidic motifs (VCA). Thus, Wsp1 exhibits domain compositions more similar to human WASP proteins than Saccharomyces cerevisiae Las17/Bee1, a WASP homolog lacking the GDB/CRIB domain. Wsp1 is not an essential protein; however, the wsp1 mutant exhibited defects in growth, cytokinesis, chitin distribution, and endocytosis and exocytosis. The wsp1 mutant was also unable to undergo genetic cross, produce the polysaccharide capsule, or secrete the enzyme urease. An in vitro phagocytosis assay showed a higher phagocytic index for the wsp1 mutant, whose ability to cause lethal infection in a murine model of cryptococcosis was also attenuated. Our studies reveal divergent evolution of WASP proteins in the fungal phylum and suggest that the conserved function of WASP proteins in the actin cytoskeleton may also impact fungal virulence.
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Kraikivski P, Slepchenko BM. Quantifying a pathway: kinetic analysis of actin dendritic nucleation. Biophys J 2010; 99:708-15. [PMID: 20682247 DOI: 10.1016/j.bpj.2010.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/03/2010] [Accepted: 05/04/2010] [Indexed: 02/07/2023] Open
Abstract
Progress in uncovering the reaction networks that underlie important cell functions is laying the groundwork for quantitative identification of protein-interaction pathways. Since direct measurement of rate constants is not always feasible, the parameters are often inferred from multiple pieces of data using kinetic analyses based on appropriate mathematical models. The success of this approach relies on the sufficiency of available experimental data for a unique parameterization of the network. The concept of a rate-limiting step is applied to the analysis of experimental data that are usually used to quantify a pathway of actin dendritic nucleation, the Arp2/3-mediated mechanism that enables rapid changes of cell shape in response to external cues. The method yields analytical descriptions of the dynamics of polymerized actin and provides insights into how the experimental curves should be analyzed. It is shown that dynamics measured by pyrene-labeled actin assays with varying Arp2/3 concentrations are equally well described by two different rate-limiting steps: 1), binding of a nucleating complex to the side of a preexisting filament; or 2), its subsequent activation. To distinguish between the alternatives, we propose experiments with varying concentrations of actin monomers, taking advantage of the fact that the number of branches in the two cases depends differently on the initial monomer concentration. The idea is tested by simulating the proposed experiments with the use of spatial stochastic modeling.
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Affiliation(s)
- Pavel Kraikivski
- Richard D. Berlin Center for Cell Analysis and Modeling, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
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