PubMed Health⌕ Search

Biomedical subjects

L M Parysek

Publications and source records attributed to L M Parysek.

29 records · Page 2Linked to original sources
PubMed1987

Characterization of intermediate filaments in PC12 cells.

A 57 kDa protein is the major polypeptide in intermediate filament (IF)-enriched cytoskeletal preparations obtained from the neuronal cell line PC12 (rat pheochromocytoma). Under the conditions used to assemble IF in vitro from other cultured cell lines, 10 nm filaments are formed after 2 cycles of disassembly-assembly from PC12 IF-enriched cytoskeletal preparations; the 57 kDa protein is the major component of the final IF pellet. The 57 kDa protein is immunologically related to the BHK-21 fibroblast 55 kDa protein (vimentin), but a comparison of the peptide maps of PC12 57 kDa and BHK 55 kDa indicates that they are different proteins. With the use of a polyclonal antiserum to the PC12 57 kDa protein, immunofluorescence observations of PC12 cells not treated with NGF reveal a juxtanuclear "knot"-like structure. After NGF treatment, the "knots" are less prominent and many IF arrays are seen coursing through the cytoplasm and extending into the neurites. These immunofluorescence observations of the distribution of IF are corroborated by fine-structural analyses. SDS-PAGE analyses indicate that IF-enriched cytoskeletons isolated from NGF-treated cells have a polypeptide composition similar to that of untreated cells, that is, the 57 kDa protein remains the major polypeptide. SDS-PAGE and immunoblotting analyses show that untreated and NGF-treated PC12 cells also contain relatively minor amounts of the 68, 150, and 200 kDa neurofilament triplet (NFT) proteins. Under immunofluorescence, only 5% of untreated PC12 cells are found to contain a juxtanuclear "knot" labeled with NFT antibodies, but with time following NGF treatment, the number of fluorescent cells increases. After about 2 weeks of NGF treatment, all of the PC12 cells appear to contain NFT antibody-positive filamentous structures. As assessed by immunofluorescence, the NFT polypeptides appear to codistribute with the 57 kDa protein in both untreated and NGF-treated PC12 cells. These data indicate that PC12 cells contain IF composed of a complex set of polypeptides, including a previously unidentified 57 kDa IF protein. While NGF may induce production of NFT polypeptides, there does not appear to be a "switch" from known mesenchymal IF polypeptide expression to NFT polypeptide expression upon stimulation of PC12 cells with NGF.

Adrenal Gland Neoplasms↗
PubMed1985

Microtubule-associated protein 4 antibody: a new marker for astroglia and oligodendroglia.

An antibody to a 240,000 dalton microtubule-associated protein, microtubule-associated protein 4, was used to illustrate the distribution of this protein in semi-thin sections of the central nervous system. Immunofluorescence microscopy indicated that microtubule-associated protein 4 was restricted to non-neuronal elements of the brain and spinal cord. Astrocytes, oligodendrocytes and "specialized" glia, including tanycytes, Bergmann glia and Muller cells, contained microtubule-associated protein 4. This distribution of microtubule-associated protein 4 in neural tissue in distinct from that described for the other major brain microtubule-associated proteins, microtubule-associated protein 1 and microtubule-associated protein 2. The reactivity of MAP 4 antibody with these glia demonstrates the antigenic relatedness of these cells and further distinguishes glia from other elements of the nervous system.

Animals↗
PubMed1984

Vimentin filaments in spreading, randomly locomoting, and f-met-leu-phe-treated neutrophils.

Human neutrophils contain intermediate filaments of the vimentin type. A cytoskeletal preparation, produced by high-salt and Triton X-100 extraction of human neutrophils, reveals a major band at 57000 Mr that comigrates with 3T3 cell vimentin on one-dimensional gels. Two-dimensional gel electrophoresis of whole neutrophils illustrates the presence of vimentin but not desmin- or keratin-filament subunits. The presence of vimentin in neutrophils is also shown by its specific staining with avian vimentin antiserum by two-dimensional gel immunoautoradiography. Indirect immunofluorescence studies show that vimentin antiserum labels an area on one side of the nucleus in spreading neutrophils. This bright area appears as a loose knot of vimentin filaments; a few filaments may radiate from the knot. In contrast to spreading neutrophils, those undergoing random locomotion contain a fine network of filaments that are located in the cytoplasm between the nucleus and the trailing end of the cell. Similarly, in chemoattractant-treated neutrophils, vimentin filaments are bundled in the uropod. Transmission electron microscopy of human neutrophil monolayers confirms the intracellular distribution of intermediate filaments as shown by immunofluorescence in spreading and randomly locomoting cells.

Autoradiography↗
PubMed1984

MAP 4: occurrence in mouse tissues.

A polyclonal antiserum to a microtubule-associated protein (MAP) from mouse neuroblastoma cells (MAP 4) was used to examine the distribution of this protein in mouse tissues. Immunoblots of neuroblastoma cell microtubule protein preparations demonstrated that the antiserum reacted with a triplet of proteins at 215,000-240,000 mol wt. Antibodies affinity purified from any of the bands showed cross-reaction with the other bands, indicating these polypeptides were all immunologically related. Antibodies specific to MAP 4 decorated microtubules in cultured murine cells fixed with glutaraldehyde, and diffuse staining was seen following treatment of cells with nocodazole. The antiserum reacted with MAP 4 in extracts of brain, heart, liver, and lung from adult mouse; the triplet in brain was more closely spaced than in the other tissues or neuroblastoma cells. In kidney, spleen, and stomach, only a single band (band 4) was labeled; this band was immunologically related to the triplet and was also present in all tissues positive for the triplet. Skeletal muscle, sperm, and peripheral blood contained no reactive polypeptides. After taxol-induced polymerization, the MAP 4 triplet was preferentially associated with the microtubule pellet whereas band 4 remained in the supernatant. These data indicate that there is tissue specificity in the distribution of MAP 4, and that some tissues contain a polypeptide related to MAP 4 (band 4) that does not bind to microtubules in vitro.

Animals↗
PubMed1984

MAP 4: a microtubule-associated protein specific for a subset of tissue microtubules.

The cytological distribution of microtubule-associated protein 4 (MAP 4) (L. M. Parysek, C. F. Asnes, J. B. Olmsted, 1984, J. Cell Biol., 99:1309-1315) in mouse tissues has been examined. Adjacent 0.5-0.9-micron sections of polyethylene glycol-embedded tissues were incubated with affinity-purified MAP 4 or tubulin antibodies, and the immunofluorescent images were compared. Tubulin antibody labeling showed distinct microtubules in all tissues examined. MAP 4 antibody also labeled microtubule-like patterns, but the extent of MAP 4 reactivity was cell type-specific within each tissue. MAP 4 antibody labeled microtubules in vascular elements of all tissues and in other cells considered to have supportive functions, including Sertoli cells in the testis and glial elements in the nervous system. Microtubule patterns were also observed in cardiac, smooth, and skeletal (eye) muscle, podocytes in kidney, Kuppfer cells in liver, and spermatid manchettes. The only MAP 4-positive cells in which the pattern was not microtubule-like were the principal cells of the collecting ducts in kidney cortex, in which diffuse fluorescence was seen. MAP 4 antibody did not react with microtubule-rich neuronal elements of the central and peripheral nervous system, skeletal muscle from anterior thigh, liver parenchymal cells, columnar epithelial cells of the small intestine, and absorptive cells of the tubular component of the nephron. These observations indicate that MAP 4 may be associated with only certain kinds of cell functions as demonstrated by the preferential distribution with microtubules of defined cell types.

Animals↗
PubMed1982

Assembly of keratin onto PtK1 cytoskeletons: evidence for an intermediate filament organizing center.

Purified keratin, solubilized in 8 M of urea, was added to Triton X-100-extracted PtK1 cells in 5 mM PIPES buffer. The buffer conditions induced assembly of keratin filaments which appear to associate with nuclei of extracted cells. These keratin fibers extend beyond the original margin of the cells and frequently form bridges between adjacent cells. Electron microscopy shows that keratin filaments associate closely with the surface of the nucleus. We suggest that the site of association between keratin and the nucleus may represent an intermediate filament organizing center.

Animals↗
PubMedDate not supplied

Complementary immunohistochemical distribution of the neurofilament triplet and novel intermediate filament proteins in the autonomic and sensory nervous system of the guinea-pig.

We have previously established that immunoreactivity for the triplet of polypeptides that comprise the class IV intermediate filament proteins (NFP-triplet) is localized in specific subpopulations of neurons in guinea-pig sensory and autonomic ganglia. Antibodies to novel neurofilament proteins, including a polyclonal antibody to a 57 kDa neuronal intermediate filament polypeptide (NIF57kD) and a monoclonal antibody (CH1) to a 150 kDa intermediate filament, or associated, protein were used in combination with antibodies to the NFP-triplet for double-labelling immunohistochemistry. The results show that different subpopulations of neurons in the guinea-pig dorsal root ganglia, coeliac ganglion and enteric ganglia can be distinguished by their complementary immunoreactivity for these proteins. In dorsal root ganglia, larger neurons are intensely immunoreactive for the NFP-triplet while immunoreactivity with CH1 and NIF57kD antibodies is restricted to the small to medium-sized neurons. In the coeliac ganglion, two regionally defined subpopulations of neurons can be distinguished by their immunoreactivity for either the NFP-triplet or NIF57kD, whereas CH1 labels all neurons with equal intensity. Three classes of morphologically distinct myenteric neuron subpopulations are also distinguished by their immunoreactivity for either the NFP-triplet, NIF57kD or CH1 antibodies. Two classes of submucous neurons are labelled both with CH1 and NIF57kD antibodies but show faint or no immunoreactivity for the NFP-triplet. It is concluded that intermediate filament protein immunoreactivity marks different subpopulations of neurons, which suggests that these proteins may have specific roles in neuronal function.

Animals↗
PubMedDate not supplied

S-cells from a highly N-myc-amplified neuroblastoma are tumorigenic in nude mice.

Some neuroblastoma tumors when cultured in vitro give rise to N (neuronal) and S (non-neuronal) cells, which differ in morphology, state of differentiation, and tumorigenicity. Previously, tumor-forming potential was shown to be characteristic of N cells but not S cells. We examined cultures of N and S cells derived from a well-characterized, N-myc-amplified human neuroblastoma cell line, NBL-W, to determine whether these N and S cells also show differential tumorigenicity in nude mice. N cells formed tumors in 94% of trials and S cells formed tumors in 56% of trials. Although S cell tumors had a longer lag phase prior to tumor development, when tumors developed, both N and S cell-derived tumors grew rapidly. These results suggest that S cells do not always represent a benign component of neuroblastomas.

Animals↗