Vanadate inhibits both intercellular adhesion and spreading on fibronectin of BHK21 cells and transformed derivatives

1991 ◽  
Vol 98 (3) ◽  
pp. 363-368
Author(s):  
J.G. Edwards ◽  
G. Campbell ◽  
A.W. Grierson ◽  
S.R. Kinn
Keyword(s):  
Cytoplasmic Dynein ◽  
Intercellular Adhesion ◽  
Metabolic Inhibition ◽  
Bhk Cells ◽  
Culture Age ◽  
Regulatory Effects

Both intercellular adhesion and spreading on fibronectin of BHK21 hamster cells are inhibited by vanadate at concentrations that cause specific regulatory effects rather than general metabolic inhibition. Inhibition of aggregation of these cells in suspension (half-maximal in 10(−5) M vanadate) is rapid and reversible. The extent of inhibition, and its decline with culture age parallel inhibition by agents that depolymerize microtubules. Vanadate also reversibly inhibits spreading of both BHK cells and transformed derivatives on fibronectin. If 10(−4) M vanadate is added to BHK cells that have spread in its absence, they remain spread, but transformed derivatives are sensitive to rounding by vanadate at 10(−6) M. The mechanisms by which vanadate inhibits both intercellular adhesion and spreading are unknown, and may be different for the two phenomena. Possible sensitive targets include cytoplasmic dynein for the former, and protein tyrosyl phosphatase for the latter.

Microtubule Dynamics and Organelle Transport in Reticulomyxa

1990 ◽  
Vol 48 (3) ◽  
pp. 194-195
Author(s):  
Yih-Tai Chen ◽  
Ursula Euteneuer ◽  
Ken B. Johnson ◽  
Michael P. Koonce ◽  
Manfred Schliwa
Keyword(s):  
Plasma Membrane ◽  
Light Microscopy ◽  
Cytoplasmic Dynein ◽  
Living Cells ◽  
Microtubule Dynamics ◽  
Model Systems ◽  
Organelle Transport ◽  
Biochemical Characteristics ◽  
Dependent Transport

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).

A pre-embedding double staining procedure used to observe the effect of fixation on the activity of intercellular adhesion molecule on T and B cells

1990 ◽  
Vol 48 (3) ◽  
pp. 378-379
Author(s):  
Jane E. Ramberg ◽  
Shigeto Tohma ◽  
Peter E. Lipsky
Keyword(s):  
B Cells ◽  
Adhesion Molecule ◽  
Colloidal Gold ◽  
Intercellular Adhesion ◽  
Intercellular Adhesion Molecule ◽  
Staining Procedure ◽  
Double Staining ◽  
T And B Cells ◽  
Microtiter Plates ◽  
Streptavidin Peroxidase

Intercellular adhesion molecule (ICAM-1) appears to be a ligand for LFA-1 dependent adhesion in T cell mediated cytotoxcity. It is found on cells of both hematopoietic and non-hematopoietic origin. While observing the activity of ICAM-1 on the surfaces of interacting T and B cells, we found that we could successfully carry out a pre-embedding double staining procedure utilizing both colloidal gold and peroxidase conjugated reagents.On 24-well microtiter plates, mitomycin-treated T4 cells were stimulated with 64.1 (anti-CD3) for one hour before the addition, in some instances, of B cells. Following a 12-48 hour incubation at 38°C, the cells were washed and then immunostained with a colloidal gold conjugated RFB-4 (anti-CD22); biotinylated R6.5 (anti-ICAM-1); followed by streptavidin/peroxidase. This method allowed us to observe two different antigens without concern about possible cross-reaction of reagents. Because we suspected ICAM-1 and R6.5 were sensitive to fixation, we tried varying concentrations of fresh paraformaldehyde before R6.5, after R6.5 and after streptavidin/peroxidase. All immunostaining and washing was done on ice with ice cold reagents.

Microtubule motors and other maps

1990 ◽  
Vol 48 (3) ◽  
pp. 1-1
Author(s):  
Richard B. Vallee
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cytoplasmic Dynein ◽  
Organelle Transport ◽  
Structural Components ◽  
Microtubule Associated Proteins ◽  
Microtubule Motors ◽  
Associated Proteins ◽  
The Subject ◽  
Intracellular Motility

Microtubules are involved in a number of forms of intracellular motility, including mitosis and bidirectional organelle transport. Purified microtubules from brain and other sources contain tubulin and a diversity of microtubule associated proteins (MAPs). Some of the high molecular weight MAPs - MAP 1A, 1B, 2A, and 2B - are long, fibrous molecules that serve as structural components of the cytamatrix. Three MAPs have recently been identified that show microtubule activated ATPase activity and produce force in association with microtubules. These proteins - kinesin, cytoplasmic dynein, and dynamin - are referred to as cytoplasmic motors. The latter two will be the subject of this talk.Cytoplasmic dynein was first identified as one of the high molecular weight brain MAPs, MAP 1C. It was determined to be structurally equivalent to ciliary and flagellar dynein, and to produce force toward the minus ends of microtubules, opposite to kinesin.

The Role of Zinc in Thyroid Hormones Metabolism

2019 ◽  
Vol 89 (1-2) ◽  
pp. 80-88 ◽  
Author(s):  
Juliana Soares Severo ◽  
Jennifer Beatriz Silva Morais ◽  
Taynáh Emannuelle Coelho de Freitas ◽  
Ana Letícia Pereira Andrade ◽  
Mayara Monte Feitosa ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Scientific Evidence ◽  
Thyroid Stimulating Hormone ◽  
Zinc Transporters ◽  
Serum Concentrations ◽  
Metabolic Adaptations ◽  
Serum T3 ◽  
Regulatory Effects ◽  
Shed Light

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

Melatonin: a novel strategy for prevention of obesity and fat accumulation in peripheral organs through the improvements of circadian rhythms and antioxidative capacity

2020 ◽  
Vol 3 (1) ◽  
pp. 58-76 ◽  
Author(s):  
Bohan Rong ◽  
Qiong Wu ◽  
Chao Sun
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Regulatory Mechanisms ◽  
Antioxidative Capacity ◽  
Unicellular Alga ◽  
Peripheral Tissues ◽  
Peripheral Organs ◽  
Regulatory Effects ◽  
Novel Strategy

Melatonin is a well-known molecule for its involvement in circadian rhythm regulation and its contribution to protection against oxidative stress in organisms including unicellular alga, animals and plants. Currently, the bio-regulatory effects of melatonin on the physiology of various peripheral tissues have drawn a great attention of scientists. Although melatonin was previously defined as a neurohormone secreted from pineal gland, recently it has been identified that virtually, every cell has the capacity to synthesize melatonin and the locally generated melatonin has multiple pathophysiological functions, including regulations of obesity and metabolic syndromes. Herein, we focus on the effects of melatonin on fat deposition in various peripheral organs/tissues. The two important regulatory mechanisms related to the topic, i.e., the improvements of circadian rhythms and antioxidative capacity will be thoroughly discussed since they are linked to several biomarkers involved in obesity and energy imbalance, including metabolism and immunity. Furthermore, several other functions of melatonin which may serve to prevent or promote obesity and energy dysmetabolism-induced pathological states are also addressed. The organs of special interest include liver, pancreas, skeletal muscle, adipose tissue and the gut microbiota.

Post-Transcriptional Regulation of Cardiac Sarcomere Protein Titin Through 3’ Untranslated Regions

2013 ◽  
Vol 9 ◽  
Author(s):  
Tara A Shrout
Keyword(s):  
Gene Expression ◽  
Transcriptional Control ◽  
Striated Muscle ◽  
Binding Capacity ◽  
Structural Features ◽  
Neonatal Rat ◽  
Regulatory Control ◽  
Untranslated Regions ◽  
Luciferase Reporter ◽  
Regulatory Effects

Titin is the largest known protein in the human body, and forms the backbone of all striated muscle sarcomeres. The elastic nature of titin is an important component of muscle compliance and functionality. A significant amount of energy is expended to synthesize titin, thus we postulate that titin gene expression is under strict regulatory control in order to conserve cellular resources. In general, gene expression is mediated in part by post-transcriptional control elements located within the 5’ and 3’ untranslated regions (UTRs) of mature mRNA. The 3’UTR in particular contains structural features that affect binding capacity to other RNA components, such as MicroRNA, which control mRNA localization, translation, and degradation. The degree and significance of the regulatory effects mediated by two determined variants of titin’s 3’ UTR were evaluated in Neonatal Rat Ventricular Myocyte and Human Embryonic Kidney cell lines. Recombinant plasmids to transfect these cells lines were engineered by insertion of the variant titin 3’UTR 431- and 1047-base pairs sequences into luciferase reporter vectors. Expression due to an unaltered reporter vector served as the control. Quantitative changes in luciferase activity due to the recombinants proportionally represented the effect titin’s respective 3’UTR conferred on downstream post-transcriptional expression relative to the control. The effect due to titin’s shorter 3’UTR sequence was inconclusive; however, results illustrated that titin’s longer 3’UTR sequence caused a 35 percent decrease in protein expression. Secondary structural analysis of the two sequences revealed differential folding patterns that affect the stability and degree of MicroRNA-binding within titin’s variant 3’UTR sequences.

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