scholarly journals The polymerization of actin. III. Aggregates of nonfilamentous actin and its associated proteins: a storage form of actin.

1976 ◽  
Vol 69 (1) ◽  
pp. 73-89 ◽  
Author(s):  
L G Tilney
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
High Molecular Weight ◽  
Careful Examination ◽  
Filament Formation ◽  
Heavy Meromyosin ◽  
Associated Proteins ◽  
High Molecular Weight Proteins ◽  
Divalent Salts ◽  
Triton X

When echinoderm sperm are treated with the detergent Triton X-100 at pH 6.4 in 10 mM phosphate buffer, the membranes are solubilized, but the actin which is located in the periacrosomal region remains as a phase-dense cup. These cups can be isolated free from the flagella and chromatin and can be solubilized by increasing the pH to 8.0 and by changing the ionic strength and type of buffer used. Since the actin does not exist in the "F" state in unreacted sperm, and since the actin remains as a unit that does not diffuse away, it must be present in the mature sperm in a bound or storage state. The actin is, in fact, associated with a pair of proteins whose mol wt are 250,000 and 230,000. When the isolated cups are digested with trypsin, these high molecular weight proteins are digested, thereby liberating the actin. The actin will polymerize if heavy meromyosin or subfragment 1 is added to a preparation of isolated cups. Evidence is presented that this pair of high molecular weight proteins is similar in molecular weight and properties to erythrocyte spectrin. Attempts at transforming the storage form of actin in the cup into filaments were only moderately successful. The best conditions for filament formation involve incubating the cup in ATP and divalent salts. Careful examination of these cups reveals that the actin polymerized preferentially on either end of oriented filaments that already exist in the cup, indicating that self-nucleation is inefficacious. I conclude that the actin can exist in the storage form by its association with spectrin-like molecules and that the actin in this state polymerizes preferentially onto existing filaments.

scholarly journals Arrangement of high molecular weight associated proteins on purified mammalian brain microtubules.

1977 ◽  
Vol 72 (3) ◽  
pp. 642-654 ◽  
Author(s):  
L A Amos
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Mammalian Brain ◽  
Lateral Interactions ◽  
High Molecular Weight Protein ◽  
Protein Molecules ◽  
Associated Proteins ◽  
Weight Protein ◽  
High Molecular Weight Proteins ◽  
Brain Microtubules

The arrangement of the high molecular weight proteins associated with the walls of reconstituted mammalian brain microtubules has been investigated by electron microscopy of negatively stained preparations. The images are found to be consistent with an arrangement whereby the high molecular weight molecules are spaced 12 tubulin dimers apart, i.e., 960 A, along each protofilament of the microtubule, in agreement with the relative stoichiometry of tubulin and high molecular weight protein. Molecules on neighbouring protofilaments seem to be staggered so that they give rise to a helical superlattice, which can be superimposed on the underlying tubulin lattice. In micrographs of disintegrating tubules there is some indication of lateral interactions between neighbouring high molecular weight molecules. When the microtubules are depolymerized into a mixture of short spirals and rings, the high molecular weight proteins appear to remain attached to their respective protofilaments.

scholarly journals High Molecular Weight Proteins ofTrypanosoma cruziReduce Cross-Reaction withLeishmaniaspp. in Serological Diagnosis Tests

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alejandra Yunuen Cervantes-Landín ◽  
Ignacio Martínez ◽  
Muslim Schabib ◽  
Bertha Espinoza
Keyword(s):  
Molecular Weight ◽  
Western Blot ◽  
High Molecular Weight ◽  
Essential Role ◽  
Serological Diagnosis ◽  
Parasitic Diseases ◽  
High Molecular Weight Proteins ◽  
Triton X ◽  
Sera Samples ◽  
Galactose Content

Chagas disease is caused by the parasiteTrypanosoma cruzi. Because of its distribution throughout Latin America, sometimes it can overlap with other parasitic diseases, such as leishmaniasis, caused byLeishmaniaspp. This might represent a problem when performing serological diagnosis, because both parasites share antigens, resulting in cross-reactions. In the present work we evaluated Mexican sera samples: 83.8% of chagasic patients recognized at least one antigen of high molecular weight (>95 kDa) when evaluated by Western blot. Proteins of 130 kDa and 160 kDa are predominantly being recognized by asymptomatic chagasic patients. When the proteins were extracted using Triton X-100 detergent, a larger number of specificT. cruziproteins were obtained. This protein fraction can be used to increase specificity to 100% in Western blot assays without losing sensitivity of the test. High molecular weight proteins ofT. cruziinclude glycoproteins with a great amount ofαMan (α-mannose),αGlc (α-glucose), GlcNAc (N-acetylglucosamine), andαGal (α-galactose) content and these structures play an essential role in antigens recognition by antibodies present in patients’ sera.

scholarly journals Ultrastructural localization of the high molecular weight proteins associated with in vitro-assembled brain microtubules

1975 ◽  
Vol 65 (1) ◽  
pp. 237-241 ◽  
Author(s):  
WL Dentler ◽  
S Granett ◽  
JL Rosenbaum
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ultrastructural Localization ◽  
Thin Sections ◽  
Microtubule Associated Proteins ◽  
Brain Extracts ◽  
Associated Proteins ◽  
High Molecular Weight Proteins ◽  
Brain Microtubules

Microtubules isolated from brain extracts by in vitro assembly (1, 19, 23) are composed principally of two tubulins and two high molecular weight proteins (microtubule-associated proteins [MAPS] 1 and 2) (2,5,7,20). Recently, it was demonstrated that in vitro-assembled brain microtubules (neurotubules) are coated with filaments (5, 7) which are similar to the filaments attached to neurotubules in situ (4, 15, 21, 24, 25), and it was suggested that the filaments are composed of the higher molecular weight MAPs (5, 7, 12). In this study, microtubules were assembled in the presence and absence of the MAPs, and thin sections of the microtubules were examined by electron microscopy. The results show that the filaments only occur on microtubules assembled in the presence of the MAPs and it is therefore concluded that the filaments are composed of the high molecular weight MAP's.

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.

INTERFERENCE BY SERUM PROTEINS WITH LH RADIOIMMUNOASSAY USING IMMUNOSORBENT

1973 ◽  
Vol 72 (2) ◽  
pp. 235-242 ◽  
Author(s):  
A. M. Reuter ◽  
J. C. Hendrick ◽  
J. Sulon ◽  
P. Franchimont
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
High Molecular Weight ◽  
Serum Proteins ◽  
Void Volume ◽  
High Molecular Weight Proteins ◽  
Serum Fractionation ◽  
Covalently Bound

ABSTRACT The percentage of LH* bound to antibodies that have been covalently bound to cellulose is diminished in the presence of LH-free human serum and sera from various species of animals. Serum fractionation studies on Sephadex G 200 show that the greatest interference comes from the proteins eluted in the void volume i. e. the high molecular weight proteins. Specifically, the gamma M globulins and the α2-macroglobulins appear to play an important role, as demonstrated by tests in which these proteins were neutralized by gamma M and α2-macroglobulin antisera.

scholarly journals Characterization of glycoconjugates of human gastrointestinal mucosa by lectins. II. Lectin binding to the isolated glycoproteins of normal and malignant gastric mucosa.

1984 ◽  
Vol 32 (7) ◽  
pp. 690-696 ◽  
Author(s):  
J Fischer ◽  
G Uhlenbruck ◽  
P J Klein ◽  
M Vierbuchen ◽  
R Fischer
Keyword(s):  
Molecular Weight ◽  
Gastric Mucosa ◽  
High Molecular Weight ◽  
Lectin Binding ◽  
Gel Filtration ◽  
Molar Ratio ◽  
Gastric Cancer Cells ◽  
Tissue Sections ◽  
Gradient Gel Electrophoresis ◽  
Triton X

Using affinity chromatography on HPA-, PNA-, Con A, and WGA-agarose columns only a part (10-30%) of the high molecular weight mucous glycoproteins could be isolated from the Triton X-100 solubilized components of normal as well as carcinomatous gastric mucosa. The main part of the mucus was not bound by the lectins, which corresponds to our earlier lectin histochemical observations on paraffin-embedded tissue sections. The lectin-bound mucous glycoproteins had a relatively lower molecular weight, ranging from about 250-1,000 kilodaltons, as indicated by polyacrylamide gradient gel electrophoresis and by gel filtration on Biogel A 1.5 m column. In gas chromatographic analysis the molar ratio of aminohexoses to galactose was found to be much higher (3:1) in the lectin-bound mucous substances than in the whole high molecular weight mucus (1:1). This finding indicates that lectins have a higher affinity to the hexosamine rich components of mucus, which may be special forms of mucous glycoprotein molecules or the incompletely glycosylated core and backbone regions of the oligosaccharide chains of mucus. Extremely high hexosamine values (10:1) were found in the PNA isolated mucus of gastric adenocarcinoma. Since it is known that PNA binds to the terminal disaccharide, beta-galactose-(1-3)-N-acetylgalactosamine, which is localized at the reducing end of the oligosaccharide chains of mucus, it is highly probable that the elongation of the oligosaccharide side chains is disturbed in gastric cancer cells.

scholarly journals Stereospecific Isotopic Labeling of Methyl Groups for NMR Spectroscopic Studies of High-Molecular-Weight Proteins

2010 ◽  
Vol 49 (11) ◽  
pp. 1958-1962 ◽  
Author(s):  
Pierre Gans ◽  
Olivier Hamelin ◽  
Remy Sounier ◽  
Isabel Ayala ◽  
M. Asunción Durá ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Isotopic Labeling ◽  
Spectroscopic Studies ◽  
Methyl Groups ◽  
High Molecular Weight Proteins

scholarly journals Identity and Origin of the ATPase activity associated with neuronal microtubules. I. The ATPase activity is associated with membrane vesicles.

1983 ◽  
Vol 96 (5) ◽  
pp. 1298-1305 ◽  
Author(s):  
D B Murphy ◽  
R R Hiebsch ◽  
K T Wallis
Keyword(s):  
Molecular Weight ◽  
Atpase Activity ◽  
High Molecular Weight ◽  
Brain Tissue ◽  
Membrane Vesicles ◽  
Microtubule Associated Proteins ◽  
In Vitro Assembly ◽  
Microtubule Protein ◽  
Associated Proteins

Microtubule protein purified from brain tissue by cycles of in vitro assembly-disassembly contains ATPase activity that has been postulated to be associated with microtubule-associated proteins (MAPs) and therefore significant for studies of microtubule-dependent motility. In this paper we demonstrate that greater than 90% of the ATPase activity is particulate in nature and may be derived from contaminating membrane vesicles. We also show that the MAPs (MAP-1, MAP-2, and tau factors) and other high molecular weight polypeptides do not contain significant amounts of ATPase activity. These findings do not support the concept of "brain dynein" or of MAPs with ATPase activity.

Sign in / Sign up

Export Citation Format

Share Document