scholarly journals Molecular Mechanisms Controlling Vascular Lumen Formation in Three-Dimensional Extracellular Matrices

2012 ◽  
Vol 195 (1-2) ◽  
pp. 122-143 ◽  
Author(s):  
Anastasia Sacharidou ◽  
Amber N. Stratman ◽  
George E. Davis
Keyword(s):  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Extracellular Matrices ◽  
Lumen Formation ◽  
Vascular Lumen

scholarly journals Cellular and Molecular Mechanisms of Vascular Lumen Formation

2009 ◽  
Vol 16 (2) ◽  
pp. 222-231 ◽  
Author(s):  
M. Luisa Iruela-Arispe ◽  
George E. Davis
Keyword(s):  
Molecular Mechanisms ◽  
Lumen Formation ◽  
Vascular Lumen

scholarly journals The Cdc42 and Rac1 GTPases are required for capillary lumen formation in three-dimensional extracellular matrices

2002 ◽  
Vol 115 (6) ◽  
pp. 1123-1136 ◽  
Author(s):  
Kayla J. Bayless ◽  
George E. Davis
Keyword(s):  
Rho Gtpases ◽  
Fluorescent Protein ◽  
Three Dimensional ◽  
Dominant Negative ◽  
Extracellular Matrices ◽  
Wild Type ◽  
Lumen Formation ◽  
Clostridium Difficile Toxin B ◽  
Green Fluorescent ◽  
Intracellular Vacuole

Here we show a requirement for the Cdc42 and Rac1 GTPases in endothelial cell (EC) morphogenesis in three-dimensional extracellular matrices. Cdc42 and Rac1 specifically regulate EC intracellular vacuole and lumen formation in both collagen and fibrin matrices. Clostridium difficile toxin B(which blocks all three Rho GTPases) completely inhibited the ability of ECs to form both vacuoles and lumens, whereas C3 transferase, a selective inhibitor of Rho, did not. Expression of either dominant-negative (N17) or constitutively active (V12) Cdc42 using recombinant adenoviruses dramatically inhibited EC vacuole and lumen formation in both collagen and fibrin matrices. Both vacuole and lumen formation initiated in ECs expressing dominant-negative(N17) Rac1 but later collapsed, indicating a role for Rac1 during later stages of vessel development. Analysis of cultures using confocal microscopy revealed green fluorescent protein-V12Rac1, -Rac1 wild-type and -Cdc42 wild-type chimeric proteins targeted to intracellular vacuole membranes during the lumen formation process. Also, expression of the verprolin-cofilin-acidic domain of N-WASP, a downstream Cdc42 effector, in ECs completely interfered with vacuole and lumen formation. These results collectively reveal a novel role for Cdc42 and Rac1 in the process of EC vacuole and lumen formation in three-dimensional extracellular matrices.

Structural Studies of Fibrinolysis by Electron and Light Microscopy

1999 ◽  
Vol 82 (08) ◽  
pp. 277-282 ◽  
Author(s):  
Yuri Veklich ◽  
Jean-Philippe Collet ◽  
Charles Francis ◽  
John W. Weisel
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Plasminogen Activator ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Degradation Products ◽  
Molecular Model ◽  
Three Dimensional ◽  
Tissue Type ◽  
Type Plasminogen Activator

IntroductionMuch is known about the fibrinolytic system that converts fibrin-bound plasminogen to the active protease, plasmin, using plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator. Plasmin then cleaves fibrin at specific sites and generates soluble fragments, many of which have been characterized, providing the basis for a molecular model of the polypeptide chain degradation.1-3 Soluble degradation products of fibrin have also been characterized by transmission electron microscopy, yielding a model for their structure.4 Moreover, high resolution, three-dimensional structures of certain fibrinogen fragments has provided a wealth of information that may be useful in understanding how various proteins bind to fibrin and the overall process of fibrinolysis (Doolittle, this volume).5,6 Both the rate of fibrinolysis and the structures of soluble derivatives are determined in part by the fibrin network structure itself. Furthermore, the activation of plasminogen by t-PA is accelerated by the conversion of fibrinogen to fibrin, and this reaction is also affected by the structure of the fibrin. For example, clots made of thin fibers have a decreased rate of conversion of plasminogen to plasmin by t-PA, and they generally are lysed more slowly than clots composed of thick fibers.7-9 Under other conditions, however, clots made of thin fibers may be lysed more rapidly.10 In addition, fibrin clots composed of abnormally thin fibers formed from certain dysfibrinogens display decreased plasminogen binding and a lower rate of fibrinolysis.11-13 Therefore, our increasing knowledge of various dysfibrinogenemias will aid our understanding of mechanisms of fibrinolysis (Matsuda, this volume).14,15 To account for these diverse observations and more fully understand the molecular basis of fibrinolysis, more knowledge of the physical changes in the fibrin matrix that precede solubilization is required. In this report, we summarize recent experiments utilizing transmission and scanning electron microscopy and confocal light microscopy to provide information about the structural changes occurring in polymerized fibrin during fibrinolysis. Many of the results of these experiments were unexpected and suggest some aspects of potential molecular mechanisms of fibrinolysis, which will also be described here.

scholarly journals Vascular Lumen Formation: Negativity Will Tear Us Apart

2010 ◽  
Vol 20 (22) ◽  
pp. R973-R975 ◽  
Author(s):  
Renée M. Robbins ◽  
Greg J. Beitel
Keyword(s):  
Lumen Formation ◽  
Vascular Lumen

Characterization of an A-type cyclin-dependent kinase gene from Dendrobium candidum

Biologia ◽  
2012 ◽  
Vol 67 (2) ◽  
Author(s):  
Gang Zhang ◽  
Chao Song ◽  
Ming-Ming Zhao ◽  
Biao Li ◽  
Shun-Xing Guo
Keyword(s):  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Postembryonic Development ◽  
Kinase Domain ◽  
Dimensional Structure ◽  
Pcr Analysis ◽  
Kinase Gene ◽  
Multiple Sequence ◽  
Dendrobium Candidum ◽  
Rapid Amplification

AbstractCyclin-dependent kinases (CDKs) play an essential role in cell cycle regulation during the embryonic and postembryonic development of organisms. To better understand the molecular mechanisms of CDKs involved in embryogenesis regulation in the endangered medicinal plant Dendrobium candidum Wall. ex Lindl., a 1229-bp full-length cDNA of an A-type CDK gene, Denca;CDKA;1, was identified using 3′ rapid amplification of cDNA end (RACE) PCR. Denca;CDKA;1 was predicted to encode a 294 amino acid residue-long protein of 33.76 kDa with an isoelectric point of 7.72. The deduced Denca;CDKA;1 protein contained a conserved serine/threonine-protein kinase domain (S-TKc) and a canonical cyclinbinding “PSTAIRE” motif. Multiple sequence alignment indicated that members of CDKA family from various plants exhibited a high degree of sequence identity ranging from 82% to 93%. A neighbor-joining phylogenetic tree showed that Denca;CDKA;1 was clustered into the plant group and was distant from the animal and fungal groups. The modeled three-dimensional structure of Denca;CDKA;1 exhibited the similar functional structure of a fold consisting of β-sheets and α-helices joined by discontinuous random coils forming two relatively independent lobes. Quantitative real-time PCR analysis revealed that Denca;CDKA;1 transcripts were the most abundant in protocorm-like bodies with 4.76 fold, followed by that in roots (4.19 fold), seeds (2.57 fold), and stems (1.57 fold). This study characterized the novel Denca;CDKA;1 gene from D. candidum for the first time and the results will be useful for further functional determination of the gene.

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