Biological functions of proteoglycans: use of specific inhibitors of proteoglycan synthesis

1991 ◽  
pp. 21-28
Author(s):  
David J. Carey
Keyword(s):  
Proteoglycan Synthesis ◽  
Biological Functions ◽  
Specific Inhibitors

Membrane–cytoskeleton interactions in cholesterol-dependent domain formation

2015 ◽  
Vol 57 ◽  
pp. 177-187 ◽  
Author(s):  
Jennifer N. Byrum ◽  
William Rodgers
Keyword(s):  
Biological Properties ◽  
Membrane Rafts ◽  
Membrane Domains ◽  
Biological Functions ◽  
Membrane Cytoskeleton ◽  
Heterogeneous Structures ◽  
Integral Role ◽  
Model Cell ◽  
Actomyosin Cytoskeleton ◽  
Dependent Domain

Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.

The Effect of Total Meniscectomy versus Caudal Pole Hemimeniscectomy on the Stifle Joint of the Sheep

1999 ◽  
Vol 12 (02) ◽  
pp. 56-63 ◽  
Author(s):  
C. R. Bellenger ◽  
P. Ghosh ◽  
Y. Numata ◽  
C. Little ◽  
D. S. Simpson
Keyword(s):  
Tissue Culture ◽  
Articular Cartilage ◽  
Fibrous Tissue ◽  
Cartilage Degeneration ◽  
Medial Compartment ◽  
Proteoglycan Synthesis ◽  
Stifle Joint ◽  
Medial Meniscectomy ◽  
Tibial Condyle ◽  
Articular Cartilage Degeneration

SummaryTotal medial meniscectomy and caudal pole hemimeniscectomy were performed on the stifle joints of twelve sheep. The two forms of meniscectomy produced a comparable degree of postoperative lameness that resolved within two weeks of the operations. After six months the sheep were euthanatised and the stifle joints examined. Fibrous tissue that replaced the excised meniscus in the total meniscectomy group did not cover as much of the medial tibial condyle as the residual cranial pole and caudal fibrous tissue observed following hemimeniscectomy. The articular cartilage from different regions within the joints was examined for gross and histological evidence of degeneration. Analyses of the articular cartilage for water content, glycosaminoglycan composition and DNA content were performed. The proteoglycan synthesis and release from explanted articular cartilage samples in tissue culture were also measured. There were significant pathological changes in the medial compartment of all meniscectomised joints. The degree of articular cartilage degeneration that was observed following total meniscectomy and caudal pole meniscectomy was similar. Caudal pole hemimeniscectomy, involving transection of the meniscus, causes the same degree of degeneration of the stifle joint that occurs following total meniscectomy.The effect of total medial meniscectomy versus caudal pole hemimeniscectomy on the stifle joint of sheep was studied experimentally. Six months after the operations gross pathology, histopathology, cartilage biochemical analysis and the rate of proteoglycan synthesis in tissue culture were used to compare the articular cartilage harvested from the meniscectomised joints. Degeneration of the articular cartilage from the medial compartment of the joints was present in both of the groups. Caudal pole hemimeniscectomy induces a comparable degree of articular cartilage degeneration to total medial meniscectomy in the sheep stifle joint.

The Interaction of β2 Glycoprotein-I and Heparin and Its Effect on β2 Glycoprotein-I Antiphospholipid Antibody Cofactor Function in Plasma

1994 ◽  
Vol 72 (04) ◽  
pp. 578-581 ◽  
Author(s):  
T McNally ◽  
S E Cotterell ◽  
I J Mackie ◽  
D A Isenberg ◽  
S J Machin
Keyword(s):  
Solid Phase ◽  
Pharmaceutical Preparations ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antiphospholipid Antibody ◽  
Biological Functions ◽  
Dermatan Sulphate ◽  
Glycoprotein I ◽  
Crossed Immunoelectrophoresis ◽  
Calcium Heparin ◽  
Cofactor Activity

Summaryβ2 glycoprotein-I (β2GPI), a cofactor for antiphospholipid antibody (aPA) binding, binds to many anionic macromolecules including heparin. The nature of this interaction with heparin is not well understood and its effect on the purported biological functions of β2GPI is unknown.We have examined the interactions of dermatan sulphate (DS) and different pharmaceutical preparations of heparin with β2GPI by crossed immunoelectrophoresis (CIE) and investigated the effect of these agents on plasma levels of p2GPI antigen (β2GPI: Ag) by a standardised enzyme linked immunosorbent assay (ELISA). P2GPI aPA cofactor activity (β2GPI:Cof) was also measured using a modified solid phase an-ti-phosphatidylserine (aPS) ELISA. CIE results confirmed a heparin-β2GPI interaction with unfractionated (UF) heparin. β2GPI:Ag levels were unaffected by any of the preparations investigated. There were no significant differences in β2GPI:Cof activities of the samples containing LMW heparins or DS but levels of β2GPI:Cof were increased in samples containing UF sodium and calcium heparin preparations (0.5 IU/ml Monoparin, p <0.05, and 10 IU/ml Liquemin and Calcipa-rine, p <0.05).

Partial Purification of a Specific Plasminogen Activator from Porcine Parotid Glands

1974 ◽  
Vol 31 (03) ◽  
pp. 403-414 ◽  
Author(s):  
Terence Cartwright
Keyword(s):  
Nucleic Acid ◽  
Salivary Glands ◽  
Plasminogen Activator ◽  
Protein Interactions ◽  
Partial Purification ◽  
Protein Protein Interactions ◽  
Parotid Glands ◽  
Two Stage ◽  
Preliminary Characterization ◽  
Specific Inhibitors

SummaryA method is described for the extraction with buffers of near physiological pH of a plasminogen activator from porcine salivary glands. Substantial purification of the activator was achieved although this was to some extent complicated by concomitant extraction of nucleic acid from the glands. Preliminary characterization experiments using specific inhibitors suggested that the activator functioned by a similar mechanism to that proposed for urokinase, but with some important kinetic differences in two-stage assay systems. The lack of reactivity of the pig gland enzyme in these systems might be related to the tendency to protein-protein interactions observed with this material.

The Effect of Alimentary Hyperlipemia on Thrombolysis in vivo

1960 ◽  
Vol 04 (02) ◽  
pp. 149-166 ◽  
Author(s):  
Nils U. Bang ◽  
Eugene E. Cliffton
Keyword(s):  
Fibrinolytic Activity ◽  
Fibrinolytic Enzyme ◽  
Enzyme Treatment ◽  
Enzyme Therapy ◽  
Fasting State ◽  
Fatty Meal ◽  
Complete Dissolution ◽  
Blood Samples ◽  
Specific Inhibitors

Summary1. The effect of a standard, potent fibrinolytic enzyme therapy has been compared in fasting and lipemic dogs.2. The standard fibrinolytic regimen resulted in the complete dissolution of all clots produced experimentally in the fasting state in 10 dogs.3. Clots formed during alimentary lipemia exhibited a markedly increased resistance to the standard fibrinolytic regimen in 6 dogs.4. An increase in anti plasmin fibrinolytic titer with concomitant decrease in spontaneous fibrinolytic activity was observed in 15 dogs following the administration of a fatty meal. No difference in fibrinolytic activity and APF titer was demonstrable in fasting and lipemic blood samples obtained during fibrinolytic enzyme treatment.5. The possibility of the presence of specific inhibitors against the fibrinolytic enzyme in clots formed during lipemia has been investigated and the evidence to support this theory is discussed.

Galactosyltransferase-1 deficiency: a novel cause of bone fragility due to impaired proteoglycan synthesis

2015 ◽  
Author(s):  
Rebecca Moon ◽  
Claire Salter ◽  
Nicola Foulds ◽  
Justin Davies
Keyword(s):  
Bone Fragility ◽  
Proteoglycan Synthesis

Proteoglycan Synthesis in Porcine Nasal Cartilage Grafts Following Nd:YAG (λ = 1.32 μm) Laser-Mediated Reshaping

2000 ◽  
Vol 71 (2) ◽  
pp. 218 ◽  
Author(s):  
Brian J. F. Wong ◽  
Thomas E. Milner ◽  
Hong K. Kim ◽  
Ken Chao ◽  
Chung-Ho Sun ◽  
...  
Keyword(s):  
Proteoglycan Synthesis ◽  
Nasal Cartilage ◽  
Cartilage Grafts

Single-Molecule Imaging of Active Mitochondrial Nitroreductases using a Photo-Crosslinking Fluorescent Sensor

2019 ◽  
Author(s):  
Zacharias Thiel ◽  
Pablo Rivera-Fuentes
Keyword(s):  
Subcellular Localization ◽  
Fluorescent Probe ◽  
Single Molecule ◽  
Mammalian Cells ◽  
Fluorescent Sensor ◽  
Biological Functions ◽  
Localization Microscopy ◽  
Drug Activation ◽  
Nitroreductase Activity ◽  
Single Molecule Localization Microscopy

Many biomacromolecules are known to cluster in microdomains with specific subcellular localization. In the case of enzymes, this clustering greatly defines their biological functions. Nitroreductases are enzymes capable of reducing nitro groups to amines and play a role in detoxification and pro-drug activation. Although nitroreductase activity has been detected in mammalian cells, the subcellular localization of this activity remains incompletely characterized. Here, we report a fluorescent probe that enables super-resolved imaging of pools of nitroreductase activity within mitochondria. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. In combination with a general photoactivatable marker of mitochondria, we performed two-color, threedimensional, single-molecule localization microscopy. These experiments allowed us to image the sub-mitochondrial organization of microdomains of nitroreductase activity.<br>

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