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V I Rodionov

Publications and source records attributed to V I Rodionov.

36 records · Page 2Linked to original sources
PubMed1986

[A cytoskeletal protein with a molecular weight of 100 kD is a component of the endosomes participating in receptor-mediated endocytosis].

Our previous paper (Rodionov et al., 1985) reported production of monoclonal antibodies RN-17 reacting in cultured fibroblasts with a protein having a molecular weight of 100 kD. Immunofluorescence and immunoelectron microscopy showed that this protein was a component of microtubules, intermediate filaments and coated vesicles. We challenged a possibility whether these coated vesicles containing the 100 kD protein may take part in the receptor-mediated endocytosis. alpha 2-Macroglobulin conjugated with fluorescein isothiocyanate or 20 nm colloidal gold particles was used as a marker of the receptor-mediated endocytosis. Mouse embryo fibroblasts or Swiss 3T3 cells were incubated with labeled alpha 2 M, fixed and "stained" with DN-17 antibody, and the distribution of alpha 2 M and 100 kD protein was examined within the same cells. In both cell lines the endocytic vesicles contained 100 kD protein and alpha 2 M. Therefore 100 kD protein is a component of endocytic vesicles. Probably this protein mediates microtubule-dependent transport of endocytic vesicles in the cells.

Animals↗
PubMed1985

Identification of a 100 kD protein associated with microtubules, intermediate filaments and coated vesicles in cultured cells.

We have obtained several hybridoma clones producing antibodies to microtubule-associated proteins (MAPs) from bovine brain. Interaction of one of these antibodies, named RN 17, with cultured cells was studied by indirect immunofluorescence and immunoelectron microscopy. RN 17 antibody recognized both high molecular weight (HMW) MAPs, MAP 1 and MAP 2, in immunoblotting reaction with brain microtubules. In lysates of cultured cells, it bound to a protein doublet with a molecular weight of 100 kD. By immunofluorescence microscopy we showed that RN 17 antibody stained cytoplasmic fibrils, mitotic spindles and small particles in the cytoplasm of various cultured cells. The cytoplasmic fibrils were identified as both microtubules and intermediate filaments by double fluorescence microscopy and by their response to colcemid and 0.6 M KCl. This identification was confirmed by immunoelectron microscopy which also showed that the particles stained by RN 17 antibody are coated vesicles. Thus, cultured non-neural cells may contain a novel protein that binds to microtubules, intermediate filaments, and coated vesicles.

Animals↗
PubMed1984

MAP2 competes with MAP1 for binding to microtubules.

A question whether MAP1 and MAP2 (the major microtubule associated proteins from mammalian brain) bind to common or distinct sites on the microtubule surface was studied. Microtubules were assembled from tubulin and MAP1 and then centrifuged through a layer of MAP2 solution under conditions where no repolymerization of tubulin with MAP2 could occur. During centrifugation, MAP2 displaced most of MAP1 on the microtubules. This implies that MAP1 is reversibly bound to microtubules and that MAP2 binding interferes with MAP1 binding. The latter means that binding sites for MAP1 and MAP2 are identical or overlap.

Animals↗
PubMed1980

High molecular weight protein MAP 2 promoting microtubule assembly in vitro is associated with microtubules in cells.

Brain high molecular weight (HMW) protein promoting microtubule assembly in vitro and identical to MAP 2 (one of the proteins which copurify with tubulin through microtubule assembly-disassembly cycles), is shown to be associated with microtubules in interphase and mitotic cells. This HMW protein was purified earlier (Kuznetsov et al., 1978), directly from bovine brain without previous obtaining total microtubule protein. Now we have obtained a monospecific antibody against it. Identity of the HMW protein with MAP 2 is inferred from SDS-electrophoresis and immunological tests; its intracellular localization is determined by indirect immunofluorescent staining of cultured bovine tracheal epithelium. the anti-MAP 2 antibody stains the same structures in the cells as the tubulin antibody: it stains the fibrillar network in interphase cells, mitotic spindle, and the stem body. No fibrillar structures in the cells treated with colchicine or vinblastine were stained with the antibody against MAP 2. Anti-MAP 2 also stains tubulin-containing paracrystals which have been formed in the vinblastine-treated cells. Therefore HMW protein MAP 2 which promotes tubulin polymerization in vitro is associated with microtubules in vivo.

Animals↗
PubMed1976

[32S Tubulin oligomer. The resistance to factors suppressing the microtubule formation].

The resistance of brain 32S tubulin oligomer to factors suppressing the microtubules formation: colchicine, CaCl2, cooling and the absence of GTP is studied. The content of oligomer in the preparation and the polymerization degree were estimated by means of analytical centrifugation. Colchicine at 25 degrees and at a concentration of 10 muM does not change and at a concentration of 100 muM only slightly decreases the content of oligomer. The oligomer dissociated (but not completely) in 1 mM colchicine. Tubulin polymerization was partly suppressed by 10 muM and completely--by 100 muM colchicine. CaCl2 at 1 and 10 mM concentrations did not destroy the oligomer but inhibited its polymerization even in lesser of these concentrations. The cooling of the incubation medium to 14 degrees C or 4 degrees C completely inhibited the polymerization and did not affect the content of oligomer in the preparations. Tbulin preparations with low amount of exogenous GTP (less than or equal 3.10(-6) M) had a usual oligomer content, whereas GTP is necessary for polymerization at concentrations exceeding 10(-4) M. Thus, the reaction of tubulin oligomerization is relatively resistant to factors preventing the microtubules assembly. This probably means that there are at least two types of intereaction between tubulin molecules: 1) bonds in microtubules which are sensitive to colchicine, Ca2+ and cold, and which are formed only in the presence of nucleosidetriphosphates; 2) bonds in 32S tubulin oligomer which are more stable and do not need in exogenous nucleotides.

Brain↗